RARE DISEASE
Botulism
Botulism
Botulism
Drug discovery
2
drugs
With orphan designations
Overview
Botulism is a neuroparalytic illness caused by potent neurotoxins produced by Clostridium botulinum and related species, characterized by symmetric descending flaccid paralysis beginning with cranial nerve deficits. It manifests through five transmission routes: foodborne (improperly preserved foods), wound (contaminated injuries/drug use), infant (intestinal colonization), iatrogenic (excessive botulinum toxin injections), and adult intestinal toxemia. Early antitoxin administration and intensive respiratory support are critical, as untreated cases progress to respiratory failure with 5-10% mortality [1][4][12].
Categories: rare infectious diseases, rare neurological diseases, rare ophthalmic disorders
Research Papers
1,362 drug discovery papers about Botulism, with 2 first-in-class and 34 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
1,362 drug discovery papers about Botulism, with 2 first-in-class and 34 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-05-20 | Development of novel 2-[(8-hydroxyquinolin-7-yl)(phenyl)methylamino]benzoic acid derivatives for inhibiting the catalytic activity of botulinum neurotoxins type B and F: in silico, in vitro & in vivo evaluation.
Botulinum neurotoxins (BoNTs) are the most pernicious toxin and category 'A' bioterrorism agent, responsible for 'botulism', a rare but fatal disease. Toxins are divided into seven toxinotypes from A-G, where A, B, E, and F are accountable for human botulism. The available treatment strategies are inadequate and ineffective for post-neuronal intoxication. We report novel 2-[(8-hydroxyquinolin-7-yl)(phenyl)methylamino]benzoic acid derivatives targetingthe catalytic site of VAMP-acting serotypes (BoNT/B and F). Inhibitory potential of the synthesized compounds was studied using a framework of in silico and experimental approaches. Inhibitory activity and binding affinity were evaluated using substrate-based cleavage and SPR assays. Compound efficacy was tested in mice through pre-mixed, prophylactic, and therapeutic strategies. Molecular dynamics simulations analyzed binding interactions, structural fluctuations, and complex stability. Endopeptidase assay revealed that the selected compounds displayed ≥ 80% inhibition of BoNT/B and F catalytic activity, with IC50 values ranging from 17.58 to 34.05 µM. SPR analysis displayed binding affinity of these molecules ranging from 8.13E-06 to 7.69E-04 for both the proteins. In the mouse bioassay, the selected molecules displayed complete protection and extension in survival of up to 20-fold. MD simulation study supported the experimental finding, revealing key interactions with HExxH and other active site residues forming stable conformation throughout the simulation time. Among them, compounds A15 and A36 were predicted to be more effective inhibitors of BoNT/B and F serotypes, respectively. These findings could lay a promising way for the development of novel therapeutics by reducing disease severity, enhancing survivability, and recovery where no post-exposure therapy presently available.
2026-01-17 | Therapeutic potential of [(8-hydroxyquinolin-7-yl)(phenyl)methylamino] benzoic acid regioisomers against human-intoxicating botulinum neurotoxin serotypes: computational modeling to in vivo protection.
Botulinum neurotoxins are class I tier bioterrorism agent, accountable for causing rare but fatal illness ‘botulism’. Out of seven serotypes, A, B, E, and F are responsible for intoxicating humans. Despite knowing harmful effects on human health for centuries, there is no commercial antidote for post-neuronal intoxication is available. In the present study, we report efficacy of regioisomers of [(8-hydroxyquinolin-7-yl)(phenyl) methylamino]benzoic acid against zinc-dependent light chain activities of BoNT/A, /B, /E & /F by combining molecular modeling with in vitro and in vivo studies. Based on structure similarity search, multiple regioisomers of 8-hydroxyquinoline were mined and screened by performing molecular docking. The best-scored compounds were analyzed for inhibitory and binding potential against these serotypes via endopeptidase and surface plasmon resonance assays. The best two compounds (NSC1011 and NSC1012) with potential inhibition and binding kinetics across serotypes were evaluated for therapeutic potential in mouse model. NSC1011 and NSC1012 (regioisomers) docking data revealed their binding energies with active domains of BoNT/A, /B, /E, and /F light chains ranging between − 9.70 to − 4.27, and − 9.84 to − 7.23 kcal/mol, respectively. The endopeptidase assay displayed ˃ 90% inhibition of catalytic activities, with the IC50 values varying among serotypes from 20 to 40 µM concentrations. SPR interaction of both compounds with the targeted proteins was observed in the range of 3.83E-05 to 4.95E-04 M. These molecules have shown complete protection at one MLD (mouse lethal dose), whereas median extension of animal survival was recorded up to 24 h when exposed to 5X MLD. The in silico, in vitro, and in vivo data reveal that NSC1011 and NSC1012 exhibited good binding affinity, stability, inhibition with promising therapeutic potential against human botulism-causing toxinotypes.
2025-10-14 | Phosphorylation of SNAP-25 at Ser187 is enhanced following its cleavage by Botulinum Neurotoxin Serotype A, promoting the dominant-negative effect of the resulting fragment.
Botulinum Neurotoxin Serotype A (BoNT/A), responsible for most human botulism cases, inhibits neurotransmitter release by cleaving the target protein SNAP-25. Previous literature demonstrated that BoNT/A mediated cleavage of a small subset of the SNAP-25 pool, resulting in SNAP-25 (1-197) fragments, is sufficient to block exocytosis. SNAP-25 (1-197) potentially competes against intact SNAP-25 for SNARE complexes and blocks neurotransmission through a dominant-negative mechanism. However, how a tiny fraction of cleaved SNAP-25 efficiently outcompetes a large pool of intact SNAP-25 remains unknown. Here, we examined the importance of SNAP-25 phosphorylation at Ser187 residue, located in the C-terminus SNARE domain, in the context of BoNT action. Our results demonstrated that Ser187-phosphorylated SNAP-25 can be efficiently cleaved in cells. Importantly, BoNT/A-cleaved SNAP-25 fragments in neuronal and non-neuronal cells are heavily phosphorylated at Ser187 and localized on the cell membrane. SNAP-25 (1-197) binds to syntaxin-1A, and the interaction is enhanced by Ser187 phosphorylation. We also found that SNAP-25 (1-197) survives longer than the BoNT/A enzymatic component itself in cells. Molecular modeling suggested that SNAP-25 (1-197), phosphorylated or not, forms stable SNARE complexes; however, Ser187 phosphorylation induces local changes in surface electrostatic potential and dynamics of the complex. This study characterizes the molecular mechanism underlying the dominant-negative effect of SNAP-25 (1-197) on neurotransmission. This research could have implications for the future development of BoNT/A inhibitors and the generation of new BoNT/A clinical formulations by regulating the abundance of Ser187 phosphorylation in cleaved SNAP-25 fragments.
2025-10-11 | Two Cases of Severe Food-Borne Botulism: Could High-Dose Methylcobalamin Accelerate Recovery?
Botulinum neurotoxins (BoNTs) are zinc-dependent endopeptidases that cleave presynaptic SNARE proteins and arrest acetylcholine release, producing flaccid paralysis with protracted recovery. We report two cases of a mother and son who developed severe food-borne botulism after eating Fesikh (traditional salted fish) with rapidly progressive descending paralysis requiring ventilation, prominent dysautonomia (hypotension responsive to fluids, bradycardia, dry mucosae, constipation with abdominal distension, as well as urinary retention), and intact consciousness. Both received trivalent antitoxin on day 2; the son was extubated on day 10, and the mother on day 16. Persistent bladder atony, fatigue, weakness, and poor concentration improved with structured physiotherapy accompanied by intramuscular methylcobalamin, which was initiated on day 1 of admission and subsequently transitioned to an eight-week course of oral methylcobalamin (500 µg daily) during the post-extubation rehabilitation phase. We discuss mechanistic plausibility and hypothesize that higher-dose methylcobalamin might accelerate neuromuscular recovery by stabilizing mitochondria, attenuating caspase-mediated apoptosis, and promoting axonal regeneration and sprouting.
2025-09-05 | Antitoxin, Supportive Care, and Adjunctive Therapies in Foodborne Botulism: A Comprehensive Systematic Review and Meta-Analysis
Background: Foodborne botulism is a rare but potentially fatal neuroparalytic illness caused by ingestion of Clostridium botulinum neurotoxins. Current treatment strategies include antitoxin administration, supportive care, and adjunctive therapies such as guanidine and 3,4-diaminopyridine. However, evidence comparing the efficacy of these interventions remain limited and inconclusive. This systematic review and meta-analysis aimed to evaluate treatment outcomes and compare the effectiveness of antitoxin, supportive care, and adjunctive therapies in managing foodborne botulism. Methods: A systematic search of PubMed and Web of Science was performed, and relevant studies were screened using predefined criteria. Data extraction and quality assessment were conducted independently by two reviewers. Pooled treatment success rates were calculated using random-effects meta-analysis with heterogeneity assessed via I² statistics. Results: 38 studies met our inclusion criteria, including case reports, case series, and observational studies. Pooled treatment success rates were high for antitoxin (95.3%, 95% CI: 91.3–97.8; p<0.001, I²=16.4%), supportive care (97.6%, 95% CI: 91.9–99.3; p<0.001, I²=0%), and guanidine (88.9%, 95% CI: 46.3–97.1; p<0.001, I²=0%). Comparative analyses showed no statistically significant differences between antitoxin alone versus combination therapy (OR 0.92, 95% CI: 0.10–8.62; p=0.94, I²=0%) or versus supportive care (OR 2.19, 95% CI: 0.28–17.14; p=0.46, I²=0%). Guanidine showed potential benefit as an adjunct, but data were limited. Conclusions: Antitoxin remains standard care for foodborne botulism, though supportive care and adjunctive treatments also show favorable outcomes. Further multicenter studies with standardized protocols are needed to optimize management.
antibodies
2026-09-10 | Development and Humanization of a Camelid-Derived Neutralizing Nanobody Targeting Botulinum Neurotoxin Type A.
Botulinum neurotoxin (BoNT), produced by Clostridium botulinum, is one of the most potent neurotoxins, causing botulism, a potentially fatal paralytic disease. Among different serotypes, BoNT/A is the most potent and the primary cause of botulism. The receptor-binding domain (Hc) of BoNT is crucial for targeting host cell receptors, making it a key therapeutic target. This study aims to develop neutralizing antibodies against BoNT/A by isolating camelid-derived nanobodies (Nbs) targeting BoNT/A-Hc (AHc). A panel of Nbs specifically targeting AHc was isolated from a camelid immune phage display library. The VHH fragments were fused with human IgG Fc (hFc) to generate VHH-hFc fusion proteins. Neutralizing activity was evaluated using a murine lethality assay following pre-incubation of antibody and toxin. Potent Nbs were humanized through homology modeling, which predicts a theoretically reduced risk of immunogenicity. The affinity of the parent and humanized antibodies to AHc was measured using biolayer interferometry (BLI). Their biophysical properties, including thermal stability and aggregation propensity, were assessed by differential scanning fluorimetry (DSF), static light scattering (SLS), and dynamic light scattering (DLS). Fifty-nine unique VHH clones were identified, four of which provided complete protection against a 20 LD50 BoNT/A challenge in mice. The most potent antibodies, 1A1 and 1A3, exhibited ED50 of 0.47 μg per mouse, corresponding to a neutralizing potency of 4.3 IU/mg. Upon humanization, the variants hA1 and hA3 showed strong binding affinities, with KD ranging from 1 to 2 nM. The humanized variant hA1 demonstrated superior neutralizing activity against BoNT/A, exhibiting an ED50 of 0.12 μg and a potency of 17.1 IU/mg, which represents an approximate four-fold increase compared to the parental antibody (1A1). Additionally, hA1 demonstrated enhanced thermal stability and minimal aggregation propensity. Humanized Nbs could serve as an attractive platform for developing novel botulism therapeutics, with potential advantages over traditional serum antitoxins in safety profile, clinical tolerability and scalable manufacturing. These favorable traits render them viable candidates for next-generation antitoxins against BoNT/A poisoning. Humanized Nb hA1 displays potent neutralizing activity and optimized biophysical properties, implying its value as a preclinical lead for botulism intervention. Nevertheless, systematic follow-up studies covering post-exposure protective efficacy, direct immunogenicity testing and comprehensive safety profiling are required to fully validate its translational prospects.
2026-07-28 | A single-case foodborne botulism outbreak caused by Clostridium botulinum type A1(B5) in diced garlic in Newfoundland and Labrador, 2024.
Foodborne botulism is a severe neuroparalytic disease caused by ingestion of foods containing botulinum neurotoxins, produced by Clostridium botulinum. In 2024, a 74-year-old woman from Newfoundland and Labrador with complete bilateral flaccid paralysis and respiratory distress was hospitalized and required intubation. From the broader differential diagnosis list, botulism was favoured prior to laboratory confirmation. Serum and feces samples initially tested negative for botulinum neurotoxins by mouse bioassay, yet viable C. botulinum type A was recovered from the feces. Food history investigation included some diced garlic in a repurposed coffee container that tested negative for botulinum neurotoxins by mouse bioassay, but viable C. botulinum type A was recovered from the sample. Both the fecal and garlic enrichment cultures were positive for bont/A and bont/B genes by real-time PCR. Whole genome sequencing revealed that both fecal and garlic isolates were highly similar with conserved gene synteny, including an intact bont/A1 gene and a disrupted (silent) bont/B5 gene encoded on the chromosome. This single-case foodborne botulism outbreak from Newfoundland and Labrador in 2024 was caused by C. botulinum type A1(B5) in diced garlic.
2026-06-17 | When BAT Precedes BIG-IV in Infant Botulism: The Need for Structured Antitoxin Decision-Pathway Reporting in Case Reports.
In infant botulism, use of equine-derived botulinum antitoxin before BIG-IV may be clinically justified when the infant-specific product is delayed. Future case reports should document the treatment decision pathway, antitoxin timing, risk-benefit justification, guardian counseling, adverse-event monitoring, and relapse-prevention rationale to make such emergency decisions reproducible.
2026-05-25 | Foodborne Botulism in an Immunocompetent Adult Following the Consumption of a Prepackaged Soup.
Botulism is a potentially fatal neuroparalytic disease that has historically been associated with outbreaks from improperly stored foods. Today, foodborne botulism in adults is rare. Because of its rarity, early symptoms may go unrecognized, leading to rapid disease progression. Prompt recognition and early administration of antitoxin are critical, as there is currently no agent that reverses the neurological damage caused by the toxin. In this case, botulism was associated with the consumption of a commercially prepackaged, non-canned soup, rather than the classic association with improperly canned foods. We also highlight the importance of early recognition and the diagnostic challenges in differentiating botulism from other neuroparalytic disorders.
2026-05-08 | The perfect storm in a coastal pond: duckweed, botulism, bird mortalities, and recurrent blooms of Euglena sanguinea.
In summer 2024, a freshwater coastal pond in northwest Spain (A Congorza, Cangas) experienced its first massive mallard (Anas platyrhynchos) mortalities, repeated in 2025. The pond is covered by Lemna minor and develops a red scum during summer. Molecular, pigment, and morphological analyses allowed identification of Euglena sanguinea as the responsible species for the latter. Water, tissues, and maggots from dead specimens were analyzed to assess physico-chemical characteristics, plankton composition, clinical signs, and toxins in order to explain these mortalities. Poor water quality parameters were determined during summer 2025 with suboxic dissolved oxygen (1.5-5.2 mg L⁻1) and high levels of biological and chemical oxygen demand (17-130 and 56-535 mg L⁻1, respectively) revealed severe degradation, failing to meet Directive EU/2024/3019 standards. Legacy persistent organic pollutants (PAHs, PCBs, OCPs, PBDEs) appeared at low, non-lethal levels. Clinical signs and analyses confirmed avian botulism (type C and C/D toxins) as the primary cause of death. LC-HRMS detected putative euglenophycin isomers in E. sanguinea pellets. Overall, these findings indicate that avian botulism is the primary cause of mallard mortalities in A Congorza. The dominance of L. minor and recurrent E. sanguinea red blooms evidence the eutrophication and severe habitat degradation potentially contributing to a multifactorial stress fatal to A. platyrhynchos.
proteins
2026-03-06 | Investigating the dual nature of Clostridium botulinum: pathogenic mechanisms and therapeutic potentials.
Clostridium botulinum (C. botulinum) is known for producing one of the strongest neurotoxins, namely botulinum neurotoxin (BoNT). This toxin is responsible for causing botulism, which is considered a severe neurological disease. This comprehensive narrative review highlights the dual nature of C. botulinum as both a serious health threat and a groundbreaking therapeutic agent. Methods: A comprehensive literature search was conducted in Google Scholar, PubMed/Medline, and Scopus (1971-2025, 2020-2025 literary focus) using keywords related to botulism pathogenesis, clinical features, and therapeutic approaches. Key findings indicate that, despite advancements in botulism management and reduced mortality due to heptavalent botulinum antitoxin (HBAT) and botulism immune globulin intravenous (BIG-IV) antitoxins, diagnostic challenges and bacterial spore resistance, particularly in group I, remain persistent. On the other hand, the discovery of serotype BoNT/X with lower toxicity in vertebrates and unique capabilities has opened new horizons in the design of safer treatments. C. botulinum represents a remarkable paradox in biology, an organism capable of producing one of the deadliest toxins known, yet simultaneously a cornerstone in modern therapeutic innovation. In fact, this toxin's dual nature is based on its selective targeting of BoNTs. In this regard, the systemic entry and distribution of this poison in the body - or, in other words, intoxication with it - poses a life-threatening aspect. On the other hand, the use of this bacterium's toxin for therapeutic and medicinal purposes is progressing due to its topical and controlled administration and entry into the body make it a targeted and effective therapeutic tool in the field of medicine. A better and more precise understanding of the mechanisms of action and, if necessary, future structural and engineered modifications in the toxin could lead to the emergence of a new generation of BoNTs that hold promise for the development of esthetic and therapeutic applications in medicine.
2026-01-31 | Iatrogenic botulism: a risk for botulinum toxin's medical use?
Botulinum toxin (BT) is infamous for its extreme toxicity. If it enters the bloodstream, it can cause botulism presenting with a typical pattern of motor and autonomic dysfunction. An international expert panel organised by IAB-Interdisciplinary Working Group for Movement Disorders explored iatrogenic botulism after BT's medical use (IB), reached conclusions and formulated recommendations. When injected into its target tissue, BT binds to gangliosides on cholinergic nerve terminals before it is internalised permanently. Small amounts of BT, however, are circulating within the bloodstream. When BT type B is applied, IB-B occurs frequently, typically affecting the autonomic nervous system. When BT type A is applied, IB-A only occurs in special circumstances, even when high doses are used. We identified 236 patients with IB-A in the literature. All IB-A was mild or moderate and fully reversible. In 212 patients, it occurred with unapproved BT use. In 116 of them, unapproved BT preparations were used, in 81, unapproved indications were treated and in 15, underlying neuromuscular impairment including myasthenia gravis, Lambert-Eaton myasthenic syndrome, amyotrophic lateral sclerosis and spinal muscle atrophy were contraindications for BT use. In 24 patients, IB-A occurred in approved BT use. Their evaluation was frequently incomplete, so that causes for IB-A often remain unclear. They may include presence of differential diagnosis, subclinical neuromuscular impairment and interference with additional diseases. When IB is suspected, proper evaluation is necessary to verify it and to identify its causes. Off-label use is common in BT therapy. However, it should be performed with caution, especially in children and when high doses are applied. High BT doses should not be applied to low volumes of target tissues, in order not to exceed the BT binding capacity.
2026-01-27 | Proteolytic Activities and Immunological Effects of Light Chains of Botulinum Neurotoxin A1, A2 and A3 Subtypes.
Botulinum neurotoxin serotype A (BoNT/A) is the most potent known neurotoxin. While its light chain (LC) catalytic domain is a prime target for next-generation vaccines and therapeutics, the functional differences among BoNT/A subtype LCs (A1, A2, A3) remain to be definitively characterized, despite notable sequence variation. This work aimed to systematically compare the proteolytic activity and immunoprotective efficacy of recombinant BoNT/A1-LC, A2-LC, and A3-LC. Recombinant A1-LC-His, A2-LC-His, A3-LC-His, and A3-LC-Twin-Strep proteins were expressed in Escherichia coli (E. coli) and purified with affinity chromatography. Their proteolytic activity was assessed via in vitro SNAP-25 cleavage assays. The protective potency of these antigens was evaluated in a mouse model. In vitro cleavage assays revealed a substrate cleavage efficiency order of A2-LC > A1-LC > A3-LC. In vivo, both A1-LC and A2-LC immunization conferred robust, broad protection against high-dose challenges with all three toxin subtypes. In stark contrast, A3-LC provided only minimal protection against its homologous toxin and none against heterologous subtypes. Crucially, the functional deficit of A3-LC was confirmed to be an intrinsic property, as the A3-LC-TS variant, designed to exclude tag-specific interference, exhibited comparable low efficacy. According to structural research, A3-LC's compromised function may be caused by a four-amino-acid loss. The inferior performance of A3-LC is inherent to its primary structure. This work identified A1-LC or A2-LC as the potential proteolytic activity molecule and vaccine antigen by demonstrating functional differences among BoNT/A subtype LCs. These findings provide crucial insights for developing subtype-specific countermeasures against botulism.
2026-01-27 | Advances in Clostridial Neurotoxins: Passage of the Intestinal Barrier and Targeting of Specific Neuronal Cells.
Clostridial neurotoxins, botulinum neurotoxins (BoNTs), and tetanus neurotoxin (TeNT) are potent toxins responsible for severe diseases, botulism and tetanus, respectively. BoNTs associate with non-toxic proteins (non-toxic non-hemagglutinin, hemagglutinins, and OrfXs), which protect BoNTs against acidic pH and protease degradation and facilitate BoNT passage through the intestinal barrier. TeNT enters motor neurons and undergoes a retrograde axonal transport until the target inhibitory interneurons in the central nervous system. BoNTs and TeNT recognize specific cell surface receptors which consist of complex sets of protein(s)-glycan-gangliosides and determine specific cell entry pathways. Recent data on structural and functional investigations of BoNT and TeNT receptors bring a better understanding of toxin trafficking in the host and entry into target neuronal cells, which is useful for the development of updated strategies of prevention and treatment of the corresponding diseases. Since clostridial neurotoxins, notably BoNTs, are important therapeutic tools, detailed knowledge of their activity opens the way of the development of engineered molecules for specific clinical applications.
2026-01-26 | Botulism induced with therapeutic doses of botulinum toxin—Case series
Botulinum toxin type A (BoNT-A), widely used in movement disorders, can rarely lead to botulism with systemic effects at therapeutic doses. We report two cases of iatrogenic botulism following abobotulinumtoxinA administration at therapeutic doses. Case 1: A 28-year-old woman with bilateral dyskinetic cerebral palsy and spasticity had been treated with BoNT-A since childhood. After receiving 820 units in 2018, she reported fatigue, reduced energy, and mild bilateral semi-ptosis, resolving spontaneously in 1 month. Similar symptoms recurred with subsequent doses of 720 and 464 units. After reducing to 360 and then 400 units, no symptoms were reported. However, in 2023, following a 464-unit dose, she again reported fatigue and semi-ptosis, lasting 15–20 days, though maintaining daily activities. Case 2: A 62-year-old woman with longstanding thoracic myelopathy had received BoNT-A since 2006, targeting lower limbs. In 2017, after receiving 880 units, she first reported mild upper limb weakness. Similar symptoms recurred with further applications, despite reduced doses, including upper limb weakness, semi-ptosis, speech changes, and mydriasis, lasting about 2 months. In 2024, after 1,000 units, she experienced atemporary inability to transfer from her wheelchair lasting for about a month. A later 900-unit dose caused milder symptoms. In some of the applications, she also reported paradoxical worsening of rigidity lasting for a few weeks. Both patients reported symptoms suggestive of systemic effects of BoNT-A at therapeutic dosing. In Case 2, overlapping symptoms between botulism and neurological baseline deficits posed diagnostic challenges, though treatment continued due to clinical benefit. This case series underscores the importance of individualized dose management and ongoing monitoring of BoNT-A treatment, especially in neurologic patients. Early recognition and the development of guidelines for managing iatrogenic botulism are essential to ensure safe and effective use.
oligonucleotides
2023-09-28 | Evaluation of Aluminium Hydroxide Nanoparticles as an Efficient Adjuvant to Potentiate the Immune Response against Clostridium botulinum Serotypes C and D Toxoid Vaccines.
Clostridium botulinum serotypes C and D cause botulism in livestock, a neuroparalytic disease that results in substantial economic losses. Vaccination with aluminium-based toxoid vaccines is widely used to control the spread of botulism. Aluminium-based adjuvants are preferred owing to their apparent stimulation of the immune responses to toxoid vaccines when compared to other adjuvants. The aim of our study was to evaluate aluminium hydroxide nanoparticles as a potential substitute for alhydrogel in the botulism bivalent vaccine. Botulism vaccines were formulated with either alhydrogel or nanoalum and comparative efficacy between the two formulations was conducted by evaluating the immune response in vaccinated guinea pigs. A significant increase in immunological parameters was observed, with the antibody titres higher in the serum of guinea pigs (20 IU/mL of anti-BoNT C/D) injected with nanoalum-containing vaccine than guinea pigs inoculated with the standard alhydrogel-containing vaccine (8.7 IU/mL and 10 IU/mL of anti-BoNT C and anti-BoNT D, respectively). Additionally, the nanoalum-containing vaccine demonstrated potency in a multivalent vaccine (20 IU/mL of anti-BoNT C/D), while the standard alhydrogel-containing vaccine showed a decline in anti-BoNT C (5 IU/mL) antibody titres.
2022-07-08 | Intramuscular delivery of formulated RNA encoding six linked nanobodies is highly protective for exposures to three Botulinum neurotoxin serotypes
Single domain antibodies (sdAbs), also called nanobodies, have substantial biophysical advantages over conventional antibodies and are increasingly being employed as components of immunotherapeutic agents. One particularly favorable property is the ability to link different sdAbs into heteromultimers. This feature allows production of single molecules capable of simultaneously targeting more than one antigen. In addition, cooperative binding of multiple linked sdAbs to non-overlapping epitopes on the same target can produce synergistic improvements in target affinity, variant specificity, and in vivo potencies. Here we seek to test the option of increased component sdAbs in these heteromultimers by testing different sdAb heterohexamers in which each of the six camelid sdAb components (VHHs) can neutralize one of three different Botulinum neurotoxin (BoNT) serotypes, A, B or E. Each heterohexamer bound all three targeted BoNT serotypes and protected mice from at least 100 MIPLD50 of each serotype. To test the potential of mRNA therapeutics encoding long sdAb heteromultimers, one heterohexamer was encoded as replicating RNA (repRNA), formulated with a cationic nanocarrier, and delivered to mice via intramuscular injection. Heterohexamer antitoxin serum expression levels were easily detected by 8 h post-treatment, peaked at 5-10 nM around two days, and persisted for more than three days. Mice treated with the formulated repRNA one day post-treatment survived challenge with 100 MIPLD50 of each toxin serotype, demonstrating the function of all six component VHHs. Use of long sdAb multimers, administered as proteins or repRNA, offer the potential for substantially improved versatility in the development of antibody-based therapeutics.
2022-03-01 | A multipathogen DNA vaccine elicits protective immune responses against two class A bioterrorism agents, anthrax and botulism.
The potential use of biological agents has become a major public health concern worldwide. According to the CDC classification, Bacillus anthracis and Clostridium botulinum, the bacterial pathogens that cause anthrax and botulism, respectively, are considered to be the most dangerous potential biological agents. Currently, there is no licensed vaccine that is well suited for mass immunization in the event of an anthrax or botulism epidemic. In the present study, we developed a dual-expression system-based multipathogen DNA vaccine that encodes the PA-D4 gene of B. anthracis and the HCt gene of C. botulinum. When the multipathogen DNA vaccine was administered to mice and guinea pigs, high level antibody responses were elicited against both PA-D4 and HCt. Analysis of the serum IgG subtype implied a combined Th1/Th2 response to both antigens, but one that was Th2 skewed. In addition, immunization with the multipathogen DNA vaccine induced effective neutralizing antibody activity against both PA-D4 and HCt. Finally, the protection efficiency of the multipathogen DNA vaccine was determined by sequential challenge with 10 LD50 of B. anthracis spores and 10 LD50 of botulinum toxin, or vice versa, and the multipathogen DNA vaccine provided higher than 50% protection against lethal challenge with both high-risk biothreat agents. Our studies suggest the strategy used for this anthrax-botulinum multipathogen DNA vaccine as a prospective approach for developing emergency vaccines that can be immediately distributed on a massive scale in response to a biothreat emergency or infectious disease outbreak. Key points • A novel multipathogen DNA vaccine was constructed against anthrax and botulism. • Robust immune responses were induced following vaccination. • Suggests a potential vaccine development strategy against biothreat agents.
2019-04-01 | Immunogenicity evaluation of rBoNT/E nanovaccine after mucosal administration.
The Botulism syndrome is caused by types A to G of botulinum neurotoxins. The binding domains of these neurotoxins are immunogenic and considered as appropriate candidate vaccines. Due to the low immunogenicity of recombinant vaccines, there have been many studies on the use of biocompatible carriers such as chitosan nanoparticles for the delivery of these vaccines. The aim of this study was evaluating the efficiency of chitosan nanoparticles as carriers for a candidate vaccine, binding domain of BoNT/E, through oral and intranasal routes.Chitosan nanoparticles containing rBoNT/E binding domain, were synthesized via ionic gelation. After administration of the nanoparticles to mice through oral and intranasal routes, antibody titers were assessed by ELISA and, finally, all groups were challenged by active botulinum neurotoxin type E.The groups that received nanoparticles containing the antigen, through oral and intranasal routes, and the group that received the bare antigen orally, were able to tolerate 5×102 folds of MLD. The intranasally immunized mice by the bare antigen were able to tolerate 2×103 folds of the toxin's MLD.It seems that the use of chitosan nanoparticles has no significant effect on the protective immunization of the mice against botulinum BoNT/E in either route (P>0.05), even intranasal administration of the bare antigen gives better mice immunization against the toxin.
2019-01-01 | Intradermal immunization with botulinum neurotoxin serotype E DNA vaccine induces humoral and cellular immunity and protects against lethal toxin challenge.
Botulinum neurotoxins (BoNTs) produced by the spore-forming, gram-positive, anaerobic bacterium Clostridium botulinum are the most toxic substances known and cause botulism, flaccid paralysis, or death. Owing to their high lethality, BoNTs are classified as category A agents by the Centers for Disease Control (CDC). Currently, there are no vaccines available to protect against BoNTs, so the rapid development of a safe and effective vaccine is important. DNA-based vaccines have recently drawn great attention because they can be developed quickly and can be applied in mass vaccination strategies to prevent disease outbreaks. Here, we report on the immunogenic and protective efficacy of a DNA vaccine, encoding a 50-kDa carboxy-terminal fragment of the BoNT serotype E heavy chain, which is delivered via an intradermal route. This plasmid DNA vaccine induced robust humoral and cellular BoNT/E-specific immune responses and completely protected animals against lethal challenge with BoNT/E. These results not only indicate that DNA vaccines could be further developed as safe and effective candidates for vaccines against BoNTs but also suggest a possible approach for developing vaccines that protect against bio-threat toxins.
other
2026-06-25 | Establishment of two Hypotheses for Gut Bacterial Alteration Process for Minimizing the Intestinal Communicable Diseases.
Intestinal communicable diseases like diarrhea, dysentery, nausea, vomiting, cholera, typhoid fever, paratyphoid fever, botulism, gastroenteritis, etc., are caused by different microbes. Intestinal microbial ecology is the most mysterious and complex environment for microbes. Bacteriophages are the dominant viruses in the intestinal microbiota. It is well established that gut microbial composition directly affects human health. Microbes use the gastrointestinal tract as niches there some factors or theories exist such as dietary, quorum sensing, and biosignaling, including biomass and biofilm production. Whereas if some microbial disbalance happens due to the effect of antibiotics or different toxin production or uninterrupted and unexpected factors dysbiosis occurs. The outcome of dysbiosis is different communicable diseases in the intestine. Alteration in microbiota can make crucial improvements in the microbiota environment and to the body's health. After reviewing evidence authors are of the opinion that two natural microbial phenomena that may be utilized as a hypothetical approach to prevent communicable diseases in the intestine, i.e., microbes-microbes competition strategy and introduction of bacteriophage to kill the target bacteria in the gut.
2025-09-01 | Efficacy and Safety of a Recombinant Protein Vaccine against Botulinum Neurotoxin Serotype A
Botulinum neurotoxin serotype A (BoNT-A), produced by Clostridium botulinum, is one of the most potent biological toxins and is a significant bioterrorism threat. Although recombinant subunit vaccines are considered promising vaccine candidates, their detailed immunogenic profile and comprehensive safety are not yet clearly characterized. In this study, we evaluated the efficacy and safety of a mutated recombinant subunit vaccine candidate, BA15, in a murine model. Immunogenicity was assessed by measuring total IgG titers, IgG subclass distribution (IgG1 and IgG2a), and antigen-induced Th1/Th2 cytokine secretion (IFN-γ, IL-4) from splenocyte cultures. Protective efficacy was determined by survival following a lethal BoNT-A challenge. Safety was rigorously evaluated via serial monitoring of body weight, food intake, neuromuscular function (grip strength and rotarod performance), and serum biochemical markers of hepatic, renal, and metabolic function. BA15 immunization elicited robust total IgG responses, with a mild predominance of IgG1 over IgG2a, indicating a slightly Th2-skewed but balanced humoral response. Splenocytes from immunized mice produced both IFN-γ and IL-4 upon antigen stimulation, reflecting concurrent Th1 and Th2 activation. BA15 vaccination conferred complete protection against the lethal BoNT-A challenge, with 100% survival and no clinical signs of botulism. Notably, intramuscular injection of BA15 was well-tolerated; no significant differences were observed in body weight, food intake, neuromuscular test performance, or serum biochemical parameters between the BA15 group and saline-injected control group, indicating a favorable safety profile. This work supports the translational potential of BA15 as a safe and effective subunit vaccine candidate for botulism prevention and addresses key preclinical requirements for further development.
2025-01-24 | Development of a Recombinant Fusion Vaccine Candidate Against Lethal Clostridium botulinum Neurotoxin Types A and B.
Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, are potent protein toxins that can cause botulism, which leads to death or neuroparalysis in humans by targeting the nervous system. BoNTs comprise three functional domains: a light-chain enzymatic domain (LC), a heavy-chain translocation domain (HCN), and a heavy-chain receptor-binding domain (HCC). The HCC domain is critical for binding to neuronal cell membrane receptors and facilitating BoNT internalization via endocytosis. Accordingly, it may serve as a vaccine candidate, inducing anti-BoNT-neutralizing antibodies in animals. Here, we aimed to develop a vaccine capable of simultaneously defending against both BoNT/A and B. We combined the HCC domains of botulinum neurotoxin type A (BoNT/A) and botulinum neurotoxin type B (BoNT/B) in Escherichia coli to produce a recombinant protein (rHCCB-L-HCCArHCcB) that offers dual protection against both toxins by inhibiting their receptor binding. To evaluate the efficacy of the vaccine, mice were immunized intramuscularly with rHCCB-L-HCCA plus alum thrice at 2-week intervals, followed by the assessment of immunogenicity and protective efficacy. The antibody titer in mice immunized with rHCCB-L-HCCA was significantly higher than that in mice immunized with alum alone, protecting them from the lethal challenges of BoNT/A (105 50% lethal dose, LD50) and B (103 LD50). These findings suggest that rHCCB-L-HCCA may simultaneously be an effective vaccine candidate against BoNT/A and B.
2024-10-25 | Specific anti-toxic immunotherapy: use in medical practice and perspectives
The results of use of approaches and means of antitoxic immunotherapy in medical practice are summarized: passive transfer of various variants of antibodies specific to toxic compounds, vaccination – specific active immunization with vaccines carrying determinants of the immunochemical specificity of target toxic compounds. The practical effectiveness of the known approaches of passive transfer and vaccination is associated with the ability of specific antibodies, by binding target bioactive compounds with pronounced toxicity, to change the availability of corresponding structures in the body-targets and, in the presence of a sufficient number of specific antibodies with high binding ability to the target compounds, neutralize their toxicity. In medical practice, polyspecific heterologous antisera or the gamma globulin fraction of antisera (extremely rare monoclonal antibodies of narrow specificity) are widely used for passive transfer as antidotes in the treatment of victims in order to prevent deaths and extensive necrosis of soft tissues at the site of the bite of poisonous snakes and insects. Active immunization – vaccination with appropriate antigenic drugs should create in immunized individuals a state of humoral immunity with the corresponding characteristics of antibody formation specific to the target compound. When a target toxic compound enters an immunized organism, it is also possible to neutralize its toxicity. The most successful experience in using the principles of active immunization as a technology for specific antitoxic therapy is associated with the practice of using toxoids for toxinemic infections. Specific practical techniques used to achieve the effectiveness of possible approaches to specific antitoxic immunotherapy in the form of passive transfer of specific antibodies or their fragments are considered: to combat lethal infections in the pathogenesis of which the toxic effects of bacterial exotoxins are significant; when treating victims of snake and insect bites, exposure to poisons of marine organisms, algae and plant toxins; in the treatment of severe intoxication with certain low molecular weight toxic substances: digoxin, colchicine, tricyclic antidepressants. The most successful experiences of using the principles of active immunization as a technology for specific antitoxic therapy, based on the use of toxoids with specificity for diphtheria, tetanus, botulism, cholera, typhoid fever, dysentery, gas gangrene and other toxinemic infections, are also considered. The fairly high immunogenicity of toxoids with the possibility of activating both constitutional and adaptive immunity has become the basis for their use as macromolecular carriers of hapten analogues of narcotic substances – a promising direction in drug addiction, in the implementation of which a number of experimental molecular and combined vaccines of opiates, methamphetamine, cocaine, and nicotine. This variant of practical efforts in medicine can be regarded as a new direction of specific antitoxic immunotherapy – an option to combat drug addiction by vaccinating drug addicts.
2024-09-12 | Immunogenicity of a pentavalent recombinant Escherichiacoli bacterin against enterotoxemia and botulism in sheep.
Producing commercial bacterins/toxoids against Clostridium spp. is laborious and hazardous. Conversely, developing prototype vaccines using purified recombinant toxoids, though safe and effective, is both laborious and costly for application in production animals. Considering that inactivated recombinant Escherichiacoli (bacterin) is a simple, cost-effective, and to be safe solution, we evaluated, for the first time, a pentavalent formulation of recombinant bacterins containing the alpha, beta, and epsilon toxins of Clostridiumperfringens and C and D neurotoxins of Clostridiumbotulinum in sheep. Subcutaneously, 18 Texel sheep received two doses (200 μg of each antigen) of recombinant bacterin (n = 7) or purified recombinant antigens (n = 6) on days 0 and 28, while the control group (n = 5) did not receive an immunization. Sera samples from days 0 (before the 1st dose), 28 (before the 2nd dose), and 56, 84, and 112 were used for measuring IgG (indirect ELISA) and neutralizing antibodies (mouse serum neutralization). Both formulations induced significant levels of IgG against all five toxins (p < 0.05) up to day 112, with peaks at days 28 and 56 post-immunization. The expected booster effect occurred only for the botulinum toxins. The neutralizing antibody titers were satisfactory against ETX (≥2 IU/ml for both formulations) and BoNT-D [5 IU/ml (bacterin) and 10 IU/ml (purified)]. While adjustments are required, the recombinant bacterin platform holds great potential for polyvalent vaccines due to its straightforward, safe, and cost-effective production, establishing it as a user-friendly technology for the veterinary immunobiological industry.
small molecules
2026-05-20 | Development of novel 2-[(8-hydroxyquinolin-7-yl)(phenyl)methylamino]benzoic acid derivatives for inhibiting the catalytic activity of botulinum neurotoxins type B and F: in silico, in vitro & in vivo evaluation.
Botulinum neurotoxins (BoNTs) are the most pernicious toxin and category 'A' bioterrorism agent, responsible for 'botulism', a rare but fatal disease. Toxins are divided into seven toxinotypes from A-G, where A, B, E, and F are accountable for human botulism. The available treatment strategies are inadequate and ineffective for post-neuronal intoxication. We report novel 2-[(8-hydroxyquinolin-7-yl)(phenyl)methylamino]benzoic acid derivatives targetingthe catalytic site of VAMP-acting serotypes (BoNT/B and F). Inhibitory potential of the synthesized compounds was studied using a framework of in silico and experimental approaches. Inhibitory activity and binding affinity were evaluated using substrate-based cleavage and SPR assays. Compound efficacy was tested in mice through pre-mixed, prophylactic, and therapeutic strategies. Molecular dynamics simulations analyzed binding interactions, structural fluctuations, and complex stability. Endopeptidase assay revealed that the selected compounds displayed ≥ 80% inhibition of BoNT/B and F catalytic activity, with IC50 values ranging from 17.58 to 34.05 µM. SPR analysis displayed binding affinity of these molecules ranging from 8.13E-06 to 7.69E-04 for both the proteins. In the mouse bioassay, the selected molecules displayed complete protection and extension in survival of up to 20-fold. MD simulation study supported the experimental finding, revealing key interactions with HExxH and other active site residues forming stable conformation throughout the simulation time. Among them, compounds A15 and A36 were predicted to be more effective inhibitors of BoNT/B and F serotypes, respectively. These findings could lay a promising way for the development of novel therapeutics by reducing disease severity, enhancing survivability, and recovery where no post-exposure therapy presently available.
2026-01-17 | Therapeutic potential of [(8-hydroxyquinolin-7-yl)(phenyl)methylamino] benzoic acid regioisomers against human-intoxicating botulinum neurotoxin serotypes: computational modeling to in vivo protection.
Botulinum neurotoxins are class I tier bioterrorism agent, accountable for causing rare but fatal illness ‘botulism’. Out of seven serotypes, A, B, E, and F are responsible for intoxicating humans. Despite knowing harmful effects on human health for centuries, there is no commercial antidote for post-neuronal intoxication is available. In the present study, we report efficacy of regioisomers of [(8-hydroxyquinolin-7-yl)(phenyl) methylamino]benzoic acid against zinc-dependent light chain activities of BoNT/A, /B, /E & /F by combining molecular modeling with in vitro and in vivo studies. Based on structure similarity search, multiple regioisomers of 8-hydroxyquinoline were mined and screened by performing molecular docking. The best-scored compounds were analyzed for inhibitory and binding potential against these serotypes via endopeptidase and surface plasmon resonance assays. The best two compounds (NSC1011 and NSC1012) with potential inhibition and binding kinetics across serotypes were evaluated for therapeutic potential in mouse model. NSC1011 and NSC1012 (regioisomers) docking data revealed their binding energies with active domains of BoNT/A, /B, /E, and /F light chains ranging between − 9.70 to − 4.27, and − 9.84 to − 7.23 kcal/mol, respectively. The endopeptidase assay displayed ˃ 90% inhibition of catalytic activities, with the IC50 values varying among serotypes from 20 to 40 µM concentrations. SPR interaction of both compounds with the targeted proteins was observed in the range of 3.83E-05 to 4.95E-04 M. These molecules have shown complete protection at one MLD (mouse lethal dose), whereas median extension of animal survival was recorded up to 24 h when exposed to 5X MLD. The in silico, in vitro, and in vivo data reveal that NSC1011 and NSC1012 exhibited good binding affinity, stability, inhibition with promising therapeutic potential against human botulism-causing toxinotypes.
2025-10-14 | Phosphorylation of SNAP-25 at Ser187 is enhanced following its cleavage by Botulinum Neurotoxin Serotype A, promoting the dominant-negative effect of the resulting fragment.
Botulinum Neurotoxin Serotype A (BoNT/A), responsible for most human botulism cases, inhibits neurotransmitter release by cleaving the target protein SNAP-25. Previous literature demonstrated that BoNT/A mediated cleavage of a small subset of the SNAP-25 pool, resulting in SNAP-25 (1-197) fragments, is sufficient to block exocytosis. SNAP-25 (1-197) potentially competes against intact SNAP-25 for SNARE complexes and blocks neurotransmission through a dominant-negative mechanism. However, how a tiny fraction of cleaved SNAP-25 efficiently outcompetes a large pool of intact SNAP-25 remains unknown. Here, we examined the importance of SNAP-25 phosphorylation at Ser187 residue, located in the C-terminus SNARE domain, in the context of BoNT action. Our results demonstrated that Ser187-phosphorylated SNAP-25 can be efficiently cleaved in cells. Importantly, BoNT/A-cleaved SNAP-25 fragments in neuronal and non-neuronal cells are heavily phosphorylated at Ser187 and localized on the cell membrane. SNAP-25 (1-197) binds to syntaxin-1A, and the interaction is enhanced by Ser187 phosphorylation. We also found that SNAP-25 (1-197) survives longer than the BoNT/A enzymatic component itself in cells. Molecular modeling suggested that SNAP-25 (1-197), phosphorylated or not, forms stable SNARE complexes; however, Ser187 phosphorylation induces local changes in surface electrostatic potential and dynamics of the complex. This study characterizes the molecular mechanism underlying the dominant-negative effect of SNAP-25 (1-197) on neurotransmission. This research could have implications for the future development of BoNT/A inhibitors and the generation of new BoNT/A clinical formulations by regulating the abundance of Ser187 phosphorylation in cleaved SNAP-25 fragments.
2025-10-11 | Two Cases of Severe Food-Borne Botulism: Could High-Dose Methylcobalamin Accelerate Recovery?
Botulinum neurotoxins (BoNTs) are zinc-dependent endopeptidases that cleave presynaptic SNARE proteins and arrest acetylcholine release, producing flaccid paralysis with protracted recovery. We report two cases of a mother and son who developed severe food-borne botulism after eating Fesikh (traditional salted fish) with rapidly progressive descending paralysis requiring ventilation, prominent dysautonomia (hypotension responsive to fluids, bradycardia, dry mucosae, constipation with abdominal distension, as well as urinary retention), and intact consciousness. Both received trivalent antitoxin on day 2; the son was extubated on day 10, and the mother on day 16. Persistent bladder atony, fatigue, weakness, and poor concentration improved with structured physiotherapy accompanied by intramuscular methylcobalamin, which was initiated on day 1 of admission and subsequently transitioned to an eight-week course of oral methylcobalamin (500 µg daily) during the post-extubation rehabilitation phase. We discuss mechanistic plausibility and hypothesize that higher-dose methylcobalamin might accelerate neuromuscular recovery by stabilizing mitochondria, attenuating caspase-mediated apoptosis, and promoting axonal regeneration and sprouting.
2025-09-05 | Antitoxin, Supportive Care, and Adjunctive Therapies in Foodborne Botulism: A Comprehensive Systematic Review and Meta-Analysis
Background: Foodborne botulism is a rare but potentially fatal neuroparalytic illness caused by ingestion of Clostridium botulinum neurotoxins. Current treatment strategies include antitoxin administration, supportive care, and adjunctive therapies such as guanidine and 3,4-diaminopyridine. However, evidence comparing the efficacy of these interventions remain limited and inconclusive. This systematic review and meta-analysis aimed to evaluate treatment outcomes and compare the effectiveness of antitoxin, supportive care, and adjunctive therapies in managing foodborne botulism. Methods: A systematic search of PubMed and Web of Science was performed, and relevant studies were screened using predefined criteria. Data extraction and quality assessment were conducted independently by two reviewers. Pooled treatment success rates were calculated using random-effects meta-analysis with heterogeneity assessed via I² statistics. Results: 38 studies met our inclusion criteria, including case reports, case series, and observational studies. Pooled treatment success rates were high for antitoxin (95.3%, 95% CI: 91.3–97.8; p<0.001, I²=16.4%), supportive care (97.6%, 95% CI: 91.9–99.3; p<0.001, I²=0%), and guanidine (88.9%, 95% CI: 46.3–97.1; p<0.001, I²=0%). Comparative analyses showed no statistically significant differences between antitoxin alone versus combination therapy (OR 0.92, 95% CI: 0.10–8.62; p=0.94, I²=0%) or versus supportive care (OR 2.19, 95% CI: 0.28–17.14; p=0.46, I²=0%). Guanidine showed potential benefit as an adjunct, but data were limited. Conclusions: Antitoxin remains standard care for foodborne botulism, though supportive care and adjunctive treatments also show favorable outcomes. Further multicenter studies with standardized protocols are needed to optimize management.
antibodies
2026-09-10 | Development and Humanization of a Camelid-Derived Neutralizing Nanobody Targeting Botulinum Neurotoxin Type A.
Botulinum neurotoxin (BoNT), produced by Clostridium botulinum, is one of the most potent neurotoxins, causing botulism, a potentially fatal paralytic disease. Among different serotypes, BoNT/A is the most potent and the primary cause of botulism. The receptor-binding domain (Hc) of BoNT is crucial for targeting host cell receptors, making it a key therapeutic target. This study aims to develop neutralizing antibodies against BoNT/A by isolating camelid-derived nanobodies (Nbs) targeting BoNT/A-Hc (AHc). A panel of Nbs specifically targeting AHc was isolated from a camelid immune phage display library. The VHH fragments were fused with human IgG Fc (hFc) to generate VHH-hFc fusion proteins. Neutralizing activity was evaluated using a murine lethality assay following pre-incubation of antibody and toxin. Potent Nbs were humanized through homology modeling, which predicts a theoretically reduced risk of immunogenicity. The affinity of the parent and humanized antibodies to AHc was measured using biolayer interferometry (BLI). Their biophysical properties, including thermal stability and aggregation propensity, were assessed by differential scanning fluorimetry (DSF), static light scattering (SLS), and dynamic light scattering (DLS). Fifty-nine unique VHH clones were identified, four of which provided complete protection against a 20 LD50 BoNT/A challenge in mice. The most potent antibodies, 1A1 and 1A3, exhibited ED50 of 0.47 μg per mouse, corresponding to a neutralizing potency of 4.3 IU/mg. Upon humanization, the variants hA1 and hA3 showed strong binding affinities, with KD ranging from 1 to 2 nM. The humanized variant hA1 demonstrated superior neutralizing activity against BoNT/A, exhibiting an ED50 of 0.12 μg and a potency of 17.1 IU/mg, which represents an approximate four-fold increase compared to the parental antibody (1A1). Additionally, hA1 demonstrated enhanced thermal stability and minimal aggregation propensity. Humanized Nbs could serve as an attractive platform for developing novel botulism therapeutics, with potential advantages over traditional serum antitoxins in safety profile, clinical tolerability and scalable manufacturing. These favorable traits render them viable candidates for next-generation antitoxins against BoNT/A poisoning. Humanized Nb hA1 displays potent neutralizing activity and optimized biophysical properties, implying its value as a preclinical lead for botulism intervention. Nevertheless, systematic follow-up studies covering post-exposure protective efficacy, direct immunogenicity testing and comprehensive safety profiling are required to fully validate its translational prospects.
2026-07-28 | A single-case foodborne botulism outbreak caused by Clostridium botulinum type A1(B5) in diced garlic in Newfoundland and Labrador, 2024.
Foodborne botulism is a severe neuroparalytic disease caused by ingestion of foods containing botulinum neurotoxins, produced by Clostridium botulinum. In 2024, a 74-year-old woman from Newfoundland and Labrador with complete bilateral flaccid paralysis and respiratory distress was hospitalized and required intubation. From the broader differential diagnosis list, botulism was favoured prior to laboratory confirmation. Serum and feces samples initially tested negative for botulinum neurotoxins by mouse bioassay, yet viable C. botulinum type A was recovered from the feces. Food history investigation included some diced garlic in a repurposed coffee container that tested negative for botulinum neurotoxins by mouse bioassay, but viable C. botulinum type A was recovered from the sample. Both the fecal and garlic enrichment cultures were positive for bont/A and bont/B genes by real-time PCR. Whole genome sequencing revealed that both fecal and garlic isolates were highly similar with conserved gene synteny, including an intact bont/A1 gene and a disrupted (silent) bont/B5 gene encoded on the chromosome. This single-case foodborne botulism outbreak from Newfoundland and Labrador in 2024 was caused by C. botulinum type A1(B5) in diced garlic.
2026-06-17 | When BAT Precedes BIG-IV in Infant Botulism: The Need for Structured Antitoxin Decision-Pathway Reporting in Case Reports.
In infant botulism, use of equine-derived botulinum antitoxin before BIG-IV may be clinically justified when the infant-specific product is delayed. Future case reports should document the treatment decision pathway, antitoxin timing, risk-benefit justification, guardian counseling, adverse-event monitoring, and relapse-prevention rationale to make such emergency decisions reproducible.
2026-05-25 | Foodborne Botulism in an Immunocompetent Adult Following the Consumption of a Prepackaged Soup.
Botulism is a potentially fatal neuroparalytic disease that has historically been associated with outbreaks from improperly stored foods. Today, foodborne botulism in adults is rare. Because of its rarity, early symptoms may go unrecognized, leading to rapid disease progression. Prompt recognition and early administration of antitoxin are critical, as there is currently no agent that reverses the neurological damage caused by the toxin. In this case, botulism was associated with the consumption of a commercially prepackaged, non-canned soup, rather than the classic association with improperly canned foods. We also highlight the importance of early recognition and the diagnostic challenges in differentiating botulism from other neuroparalytic disorders.
2026-05-08 | The perfect storm in a coastal pond: duckweed, botulism, bird mortalities, and recurrent blooms of Euglena sanguinea.
In summer 2024, a freshwater coastal pond in northwest Spain (A Congorza, Cangas) experienced its first massive mallard (Anas platyrhynchos) mortalities, repeated in 2025. The pond is covered by Lemna minor and develops a red scum during summer. Molecular, pigment, and morphological analyses allowed identification of Euglena sanguinea as the responsible species for the latter. Water, tissues, and maggots from dead specimens were analyzed to assess physico-chemical characteristics, plankton composition, clinical signs, and toxins in order to explain these mortalities. Poor water quality parameters were determined during summer 2025 with suboxic dissolved oxygen (1.5-5.2 mg L⁻1) and high levels of biological and chemical oxygen demand (17-130 and 56-535 mg L⁻1, respectively) revealed severe degradation, failing to meet Directive EU/2024/3019 standards. Legacy persistent organic pollutants (PAHs, PCBs, OCPs, PBDEs) appeared at low, non-lethal levels. Clinical signs and analyses confirmed avian botulism (type C and C/D toxins) as the primary cause of death. LC-HRMS detected putative euglenophycin isomers in E. sanguinea pellets. Overall, these findings indicate that avian botulism is the primary cause of mallard mortalities in A Congorza. The dominance of L. minor and recurrent E. sanguinea red blooms evidence the eutrophication and severe habitat degradation potentially contributing to a multifactorial stress fatal to A. platyrhynchos.
proteins
2026-03-06 | Investigating the dual nature of Clostridium botulinum: pathogenic mechanisms and therapeutic potentials.
Clostridium botulinum (C. botulinum) is known for producing one of the strongest neurotoxins, namely botulinum neurotoxin (BoNT). This toxin is responsible for causing botulism, which is considered a severe neurological disease. This comprehensive narrative review highlights the dual nature of C. botulinum as both a serious health threat and a groundbreaking therapeutic agent. Methods: A comprehensive literature search was conducted in Google Scholar, PubMed/Medline, and Scopus (1971-2025, 2020-2025 literary focus) using keywords related to botulism pathogenesis, clinical features, and therapeutic approaches. Key findings indicate that, despite advancements in botulism management and reduced mortality due to heptavalent botulinum antitoxin (HBAT) and botulism immune globulin intravenous (BIG-IV) antitoxins, diagnostic challenges and bacterial spore resistance, particularly in group I, remain persistent. On the other hand, the discovery of serotype BoNT/X with lower toxicity in vertebrates and unique capabilities has opened new horizons in the design of safer treatments. C. botulinum represents a remarkable paradox in biology, an organism capable of producing one of the deadliest toxins known, yet simultaneously a cornerstone in modern therapeutic innovation. In fact, this toxin's dual nature is based on its selective targeting of BoNTs. In this regard, the systemic entry and distribution of this poison in the body - or, in other words, intoxication with it - poses a life-threatening aspect. On the other hand, the use of this bacterium's toxin for therapeutic and medicinal purposes is progressing due to its topical and controlled administration and entry into the body make it a targeted and effective therapeutic tool in the field of medicine. A better and more precise understanding of the mechanisms of action and, if necessary, future structural and engineered modifications in the toxin could lead to the emergence of a new generation of BoNTs that hold promise for the development of esthetic and therapeutic applications in medicine.
2026-01-31 | Iatrogenic botulism: a risk for botulinum toxin's medical use?
Botulinum toxin (BT) is infamous for its extreme toxicity. If it enters the bloodstream, it can cause botulism presenting with a typical pattern of motor and autonomic dysfunction. An international expert panel organised by IAB-Interdisciplinary Working Group for Movement Disorders explored iatrogenic botulism after BT's medical use (IB), reached conclusions and formulated recommendations. When injected into its target tissue, BT binds to gangliosides on cholinergic nerve terminals before it is internalised permanently. Small amounts of BT, however, are circulating within the bloodstream. When BT type B is applied, IB-B occurs frequently, typically affecting the autonomic nervous system. When BT type A is applied, IB-A only occurs in special circumstances, even when high doses are used. We identified 236 patients with IB-A in the literature. All IB-A was mild or moderate and fully reversible. In 212 patients, it occurred with unapproved BT use. In 116 of them, unapproved BT preparations were used, in 81, unapproved indications were treated and in 15, underlying neuromuscular impairment including myasthenia gravis, Lambert-Eaton myasthenic syndrome, amyotrophic lateral sclerosis and spinal muscle atrophy were contraindications for BT use. In 24 patients, IB-A occurred in approved BT use. Their evaluation was frequently incomplete, so that causes for IB-A often remain unclear. They may include presence of differential diagnosis, subclinical neuromuscular impairment and interference with additional diseases. When IB is suspected, proper evaluation is necessary to verify it and to identify its causes. Off-label use is common in BT therapy. However, it should be performed with caution, especially in children and when high doses are applied. High BT doses should not be applied to low volumes of target tissues, in order not to exceed the BT binding capacity.
2026-01-27 | Proteolytic Activities and Immunological Effects of Light Chains of Botulinum Neurotoxin A1, A2 and A3 Subtypes.
Botulinum neurotoxin serotype A (BoNT/A) is the most potent known neurotoxin. While its light chain (LC) catalytic domain is a prime target for next-generation vaccines and therapeutics, the functional differences among BoNT/A subtype LCs (A1, A2, A3) remain to be definitively characterized, despite notable sequence variation. This work aimed to systematically compare the proteolytic activity and immunoprotective efficacy of recombinant BoNT/A1-LC, A2-LC, and A3-LC. Recombinant A1-LC-His, A2-LC-His, A3-LC-His, and A3-LC-Twin-Strep proteins were expressed in Escherichia coli (E. coli) and purified with affinity chromatography. Their proteolytic activity was assessed via in vitro SNAP-25 cleavage assays. The protective potency of these antigens was evaluated in a mouse model. In vitro cleavage assays revealed a substrate cleavage efficiency order of A2-LC > A1-LC > A3-LC. In vivo, both A1-LC and A2-LC immunization conferred robust, broad protection against high-dose challenges with all three toxin subtypes. In stark contrast, A3-LC provided only minimal protection against its homologous toxin and none against heterologous subtypes. Crucially, the functional deficit of A3-LC was confirmed to be an intrinsic property, as the A3-LC-TS variant, designed to exclude tag-specific interference, exhibited comparable low efficacy. According to structural research, A3-LC's compromised function may be caused by a four-amino-acid loss. The inferior performance of A3-LC is inherent to its primary structure. This work identified A1-LC or A2-LC as the potential proteolytic activity molecule and vaccine antigen by demonstrating functional differences among BoNT/A subtype LCs. These findings provide crucial insights for developing subtype-specific countermeasures against botulism.
2026-01-27 | Advances in Clostridial Neurotoxins: Passage of the Intestinal Barrier and Targeting of Specific Neuronal Cells.
Clostridial neurotoxins, botulinum neurotoxins (BoNTs), and tetanus neurotoxin (TeNT) are potent toxins responsible for severe diseases, botulism and tetanus, respectively. BoNTs associate with non-toxic proteins (non-toxic non-hemagglutinin, hemagglutinins, and OrfXs), which protect BoNTs against acidic pH and protease degradation and facilitate BoNT passage through the intestinal barrier. TeNT enters motor neurons and undergoes a retrograde axonal transport until the target inhibitory interneurons in the central nervous system. BoNTs and TeNT recognize specific cell surface receptors which consist of complex sets of protein(s)-glycan-gangliosides and determine specific cell entry pathways. Recent data on structural and functional investigations of BoNT and TeNT receptors bring a better understanding of toxin trafficking in the host and entry into target neuronal cells, which is useful for the development of updated strategies of prevention and treatment of the corresponding diseases. Since clostridial neurotoxins, notably BoNTs, are important therapeutic tools, detailed knowledge of their activity opens the way of the development of engineered molecules for specific clinical applications.
2026-01-26 | Botulism induced with therapeutic doses of botulinum toxin—Case series
Botulinum toxin type A (BoNT-A), widely used in movement disorders, can rarely lead to botulism with systemic effects at therapeutic doses. We report two cases of iatrogenic botulism following abobotulinumtoxinA administration at therapeutic doses. Case 1: A 28-year-old woman with bilateral dyskinetic cerebral palsy and spasticity had been treated with BoNT-A since childhood. After receiving 820 units in 2018, she reported fatigue, reduced energy, and mild bilateral semi-ptosis, resolving spontaneously in 1 month. Similar symptoms recurred with subsequent doses of 720 and 464 units. After reducing to 360 and then 400 units, no symptoms were reported. However, in 2023, following a 464-unit dose, she again reported fatigue and semi-ptosis, lasting 15–20 days, though maintaining daily activities. Case 2: A 62-year-old woman with longstanding thoracic myelopathy had received BoNT-A since 2006, targeting lower limbs. In 2017, after receiving 880 units, she first reported mild upper limb weakness. Similar symptoms recurred with further applications, despite reduced doses, including upper limb weakness, semi-ptosis, speech changes, and mydriasis, lasting about 2 months. In 2024, after 1,000 units, she experienced atemporary inability to transfer from her wheelchair lasting for about a month. A later 900-unit dose caused milder symptoms. In some of the applications, she also reported paradoxical worsening of rigidity lasting for a few weeks. Both patients reported symptoms suggestive of systemic effects of BoNT-A at therapeutic dosing. In Case 2, overlapping symptoms between botulism and neurological baseline deficits posed diagnostic challenges, though treatment continued due to clinical benefit. This case series underscores the importance of individualized dose management and ongoing monitoring of BoNT-A treatment, especially in neurologic patients. Early recognition and the development of guidelines for managing iatrogenic botulism are essential to ensure safe and effective use.
oligonucleotides
2023-09-28 | Evaluation of Aluminium Hydroxide Nanoparticles as an Efficient Adjuvant to Potentiate the Immune Response against Clostridium botulinum Serotypes C and D Toxoid Vaccines.
Clostridium botulinum serotypes C and D cause botulism in livestock, a neuroparalytic disease that results in substantial economic losses. Vaccination with aluminium-based toxoid vaccines is widely used to control the spread of botulism. Aluminium-based adjuvants are preferred owing to their apparent stimulation of the immune responses to toxoid vaccines when compared to other adjuvants. The aim of our study was to evaluate aluminium hydroxide nanoparticles as a potential substitute for alhydrogel in the botulism bivalent vaccine. Botulism vaccines were formulated with either alhydrogel or nanoalum and comparative efficacy between the two formulations was conducted by evaluating the immune response in vaccinated guinea pigs. A significant increase in immunological parameters was observed, with the antibody titres higher in the serum of guinea pigs (20 IU/mL of anti-BoNT C/D) injected with nanoalum-containing vaccine than guinea pigs inoculated with the standard alhydrogel-containing vaccine (8.7 IU/mL and 10 IU/mL of anti-BoNT C and anti-BoNT D, respectively). Additionally, the nanoalum-containing vaccine demonstrated potency in a multivalent vaccine (20 IU/mL of anti-BoNT C/D), while the standard alhydrogel-containing vaccine showed a decline in anti-BoNT C (5 IU/mL) antibody titres.
2022-07-08 | Intramuscular delivery of formulated RNA encoding six linked nanobodies is highly protective for exposures to three Botulinum neurotoxin serotypes
Single domain antibodies (sdAbs), also called nanobodies, have substantial biophysical advantages over conventional antibodies and are increasingly being employed as components of immunotherapeutic agents. One particularly favorable property is the ability to link different sdAbs into heteromultimers. This feature allows production of single molecules capable of simultaneously targeting more than one antigen. In addition, cooperative binding of multiple linked sdAbs to non-overlapping epitopes on the same target can produce synergistic improvements in target affinity, variant specificity, and in vivo potencies. Here we seek to test the option of increased component sdAbs in these heteromultimers by testing different sdAb heterohexamers in which each of the six camelid sdAb components (VHHs) can neutralize one of three different Botulinum neurotoxin (BoNT) serotypes, A, B or E. Each heterohexamer bound all three targeted BoNT serotypes and protected mice from at least 100 MIPLD50 of each serotype. To test the potential of mRNA therapeutics encoding long sdAb heteromultimers, one heterohexamer was encoded as replicating RNA (repRNA), formulated with a cationic nanocarrier, and delivered to mice via intramuscular injection. Heterohexamer antitoxin serum expression levels were easily detected by 8 h post-treatment, peaked at 5-10 nM around two days, and persisted for more than three days. Mice treated with the formulated repRNA one day post-treatment survived challenge with 100 MIPLD50 of each toxin serotype, demonstrating the function of all six component VHHs. Use of long sdAb multimers, administered as proteins or repRNA, offer the potential for substantially improved versatility in the development of antibody-based therapeutics.
2022-03-01 | A multipathogen DNA vaccine elicits protective immune responses against two class A bioterrorism agents, anthrax and botulism.
The potential use of biological agents has become a major public health concern worldwide. According to the CDC classification, Bacillus anthracis and Clostridium botulinum, the bacterial pathogens that cause anthrax and botulism, respectively, are considered to be the most dangerous potential biological agents. Currently, there is no licensed vaccine that is well suited for mass immunization in the event of an anthrax or botulism epidemic. In the present study, we developed a dual-expression system-based multipathogen DNA vaccine that encodes the PA-D4 gene of B. anthracis and the HCt gene of C. botulinum. When the multipathogen DNA vaccine was administered to mice and guinea pigs, high level antibody responses were elicited against both PA-D4 and HCt. Analysis of the serum IgG subtype implied a combined Th1/Th2 response to both antigens, but one that was Th2 skewed. In addition, immunization with the multipathogen DNA vaccine induced effective neutralizing antibody activity against both PA-D4 and HCt. Finally, the protection efficiency of the multipathogen DNA vaccine was determined by sequential challenge with 10 LD50 of B. anthracis spores and 10 LD50 of botulinum toxin, or vice versa, and the multipathogen DNA vaccine provided higher than 50% protection against lethal challenge with both high-risk biothreat agents. Our studies suggest the strategy used for this anthrax-botulinum multipathogen DNA vaccine as a prospective approach for developing emergency vaccines that can be immediately distributed on a massive scale in response to a biothreat emergency or infectious disease outbreak. Key points • A novel multipathogen DNA vaccine was constructed against anthrax and botulism. • Robust immune responses were induced following vaccination. • Suggests a potential vaccine development strategy against biothreat agents.
2019-04-01 | Immunogenicity evaluation of rBoNT/E nanovaccine after mucosal administration.
The Botulism syndrome is caused by types A to G of botulinum neurotoxins. The binding domains of these neurotoxins are immunogenic and considered as appropriate candidate vaccines. Due to the low immunogenicity of recombinant vaccines, there have been many studies on the use of biocompatible carriers such as chitosan nanoparticles for the delivery of these vaccines. The aim of this study was evaluating the efficiency of chitosan nanoparticles as carriers for a candidate vaccine, binding domain of BoNT/E, through oral and intranasal routes.Chitosan nanoparticles containing rBoNT/E binding domain, were synthesized via ionic gelation. After administration of the nanoparticles to mice through oral and intranasal routes, antibody titers were assessed by ELISA and, finally, all groups were challenged by active botulinum neurotoxin type E.The groups that received nanoparticles containing the antigen, through oral and intranasal routes, and the group that received the bare antigen orally, were able to tolerate 5×102 folds of MLD. The intranasally immunized mice by the bare antigen were able to tolerate 2×103 folds of the toxin's MLD.It seems that the use of chitosan nanoparticles has no significant effect on the protective immunization of the mice against botulinum BoNT/E in either route (P>0.05), even intranasal administration of the bare antigen gives better mice immunization against the toxin.
2019-01-01 | Intradermal immunization with botulinum neurotoxin serotype E DNA vaccine induces humoral and cellular immunity and protects against lethal toxin challenge.
Botulinum neurotoxins (BoNTs) produced by the spore-forming, gram-positive, anaerobic bacterium Clostridium botulinum are the most toxic substances known and cause botulism, flaccid paralysis, or death. Owing to their high lethality, BoNTs are classified as category A agents by the Centers for Disease Control (CDC). Currently, there are no vaccines available to protect against BoNTs, so the rapid development of a safe and effective vaccine is important. DNA-based vaccines have recently drawn great attention because they can be developed quickly and can be applied in mass vaccination strategies to prevent disease outbreaks. Here, we report on the immunogenic and protective efficacy of a DNA vaccine, encoding a 50-kDa carboxy-terminal fragment of the BoNT serotype E heavy chain, which is delivered via an intradermal route. This plasmid DNA vaccine induced robust humoral and cellular BoNT/E-specific immune responses and completely protected animals against lethal challenge with BoNT/E. These results not only indicate that DNA vaccines could be further developed as safe and effective candidates for vaccines against BoNTs but also suggest a possible approach for developing vaccines that protect against bio-threat toxins.
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2026-06-25 | Establishment of two Hypotheses for Gut Bacterial Alteration Process for Minimizing the Intestinal Communicable Diseases.
Intestinal communicable diseases like diarrhea, dysentery, nausea, vomiting, cholera, typhoid fever, paratyphoid fever, botulism, gastroenteritis, etc., are caused by different microbes. Intestinal microbial ecology is the most mysterious and complex environment for microbes. Bacteriophages are the dominant viruses in the intestinal microbiota. It is well established that gut microbial composition directly affects human health. Microbes use the gastrointestinal tract as niches there some factors or theories exist such as dietary, quorum sensing, and biosignaling, including biomass and biofilm production. Whereas if some microbial disbalance happens due to the effect of antibiotics or different toxin production or uninterrupted and unexpected factors dysbiosis occurs. The outcome of dysbiosis is different communicable diseases in the intestine. Alteration in microbiota can make crucial improvements in the microbiota environment and to the body's health. After reviewing evidence authors are of the opinion that two natural microbial phenomena that may be utilized as a hypothetical approach to prevent communicable diseases in the intestine, i.e., microbes-microbes competition strategy and introduction of bacteriophage to kill the target bacteria in the gut.
2025-09-01 | Efficacy and Safety of a Recombinant Protein Vaccine against Botulinum Neurotoxin Serotype A
Botulinum neurotoxin serotype A (BoNT-A), produced by Clostridium botulinum, is one of the most potent biological toxins and is a significant bioterrorism threat. Although recombinant subunit vaccines are considered promising vaccine candidates, their detailed immunogenic profile and comprehensive safety are not yet clearly characterized. In this study, we evaluated the efficacy and safety of a mutated recombinant subunit vaccine candidate, BA15, in a murine model. Immunogenicity was assessed by measuring total IgG titers, IgG subclass distribution (IgG1 and IgG2a), and antigen-induced Th1/Th2 cytokine secretion (IFN-γ, IL-4) from splenocyte cultures. Protective efficacy was determined by survival following a lethal BoNT-A challenge. Safety was rigorously evaluated via serial monitoring of body weight, food intake, neuromuscular function (grip strength and rotarod performance), and serum biochemical markers of hepatic, renal, and metabolic function. BA15 immunization elicited robust total IgG responses, with a mild predominance of IgG1 over IgG2a, indicating a slightly Th2-skewed but balanced humoral response. Splenocytes from immunized mice produced both IFN-γ and IL-4 upon antigen stimulation, reflecting concurrent Th1 and Th2 activation. BA15 vaccination conferred complete protection against the lethal BoNT-A challenge, with 100% survival and no clinical signs of botulism. Notably, intramuscular injection of BA15 was well-tolerated; no significant differences were observed in body weight, food intake, neuromuscular test performance, or serum biochemical parameters between the BA15 group and saline-injected control group, indicating a favorable safety profile. This work supports the translational potential of BA15 as a safe and effective subunit vaccine candidate for botulism prevention and addresses key preclinical requirements for further development.
2025-01-24 | Development of a Recombinant Fusion Vaccine Candidate Against Lethal Clostridium botulinum Neurotoxin Types A and B.
Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, are potent protein toxins that can cause botulism, which leads to death or neuroparalysis in humans by targeting the nervous system. BoNTs comprise three functional domains: a light-chain enzymatic domain (LC), a heavy-chain translocation domain (HCN), and a heavy-chain receptor-binding domain (HCC). The HCC domain is critical for binding to neuronal cell membrane receptors and facilitating BoNT internalization via endocytosis. Accordingly, it may serve as a vaccine candidate, inducing anti-BoNT-neutralizing antibodies in animals. Here, we aimed to develop a vaccine capable of simultaneously defending against both BoNT/A and B. We combined the HCC domains of botulinum neurotoxin type A (BoNT/A) and botulinum neurotoxin type B (BoNT/B) in Escherichia coli to produce a recombinant protein (rHCCB-L-HCCArHCcB) that offers dual protection against both toxins by inhibiting their receptor binding. To evaluate the efficacy of the vaccine, mice were immunized intramuscularly with rHCCB-L-HCCA plus alum thrice at 2-week intervals, followed by the assessment of immunogenicity and protective efficacy. The antibody titer in mice immunized with rHCCB-L-HCCA was significantly higher than that in mice immunized with alum alone, protecting them from the lethal challenges of BoNT/A (105 50% lethal dose, LD50) and B (103 LD50). These findings suggest that rHCCB-L-HCCA may simultaneously be an effective vaccine candidate against BoNT/A and B.
2024-10-25 | Specific anti-toxic immunotherapy: use in medical practice and perspectives
The results of use of approaches and means of antitoxic immunotherapy in medical practice are summarized: passive transfer of various variants of antibodies specific to toxic compounds, vaccination – specific active immunization with vaccines carrying determinants of the immunochemical specificity of target toxic compounds. The practical effectiveness of the known approaches of passive transfer and vaccination is associated with the ability of specific antibodies, by binding target bioactive compounds with pronounced toxicity, to change the availability of corresponding structures in the body-targets and, in the presence of a sufficient number of specific antibodies with high binding ability to the target compounds, neutralize their toxicity. In medical practice, polyspecific heterologous antisera or the gamma globulin fraction of antisera (extremely rare monoclonal antibodies of narrow specificity) are widely used for passive transfer as antidotes in the treatment of victims in order to prevent deaths and extensive necrosis of soft tissues at the site of the bite of poisonous snakes and insects. Active immunization – vaccination with appropriate antigenic drugs should create in immunized individuals a state of humoral immunity with the corresponding characteristics of antibody formation specific to the target compound. When a target toxic compound enters an immunized organism, it is also possible to neutralize its toxicity. The most successful experience in using the principles of active immunization as a technology for specific antitoxic therapy is associated with the practice of using toxoids for toxinemic infections. Specific practical techniques used to achieve the effectiveness of possible approaches to specific antitoxic immunotherapy in the form of passive transfer of specific antibodies or their fragments are considered: to combat lethal infections in the pathogenesis of which the toxic effects of bacterial exotoxins are significant; when treating victims of snake and insect bites, exposure to poisons of marine organisms, algae and plant toxins; in the treatment of severe intoxication with certain low molecular weight toxic substances: digoxin, colchicine, tricyclic antidepressants. The most successful experiences of using the principles of active immunization as a technology for specific antitoxic therapy, based on the use of toxoids with specificity for diphtheria, tetanus, botulism, cholera, typhoid fever, dysentery, gas gangrene and other toxinemic infections, are also considered. The fairly high immunogenicity of toxoids with the possibility of activating both constitutional and adaptive immunity has become the basis for their use as macromolecular carriers of hapten analogues of narcotic substances – a promising direction in drug addiction, in the implementation of which a number of experimental molecular and combined vaccines of opiates, methamphetamine, cocaine, and nicotine. This variant of practical efforts in medicine can be regarded as a new direction of specific antitoxic immunotherapy – an option to combat drug addiction by vaccinating drug addicts.
2024-09-12 | Immunogenicity of a pentavalent recombinant Escherichiacoli bacterin against enterotoxemia and botulism in sheep.
Producing commercial bacterins/toxoids against Clostridium spp. is laborious and hazardous. Conversely, developing prototype vaccines using purified recombinant toxoids, though safe and effective, is both laborious and costly for application in production animals. Considering that inactivated recombinant Escherichiacoli (bacterin) is a simple, cost-effective, and to be safe solution, we evaluated, for the first time, a pentavalent formulation of recombinant bacterins containing the alpha, beta, and epsilon toxins of Clostridiumperfringens and C and D neurotoxins of Clostridiumbotulinum in sheep. Subcutaneously, 18 Texel sheep received two doses (200 μg of each antigen) of recombinant bacterin (n = 7) or purified recombinant antigens (n = 6) on days 0 and 28, while the control group (n = 5) did not receive an immunization. Sera samples from days 0 (before the 1st dose), 28 (before the 2nd dose), and 56, 84, and 112 were used for measuring IgG (indirect ELISA) and neutralizing antibodies (mouse serum neutralization). Both formulations induced significant levels of IgG against all five toxins (p < 0.05) up to day 112, with peaks at days 28 and 56 post-immunization. The expected booster effect occurred only for the botulinum toxins. The neutralizing antibody titers were satisfactory against ETX (≥2 IU/ml for both formulations) and BoNT-D [5 IU/ml (bacterin) and 10 IU/ml (purified)]. While adjustments are required, the recombinant bacterin platform holds great potential for polyvalent vaccines due to its straightforward, safe, and cost-effective production, establishing it as a user-friendly technology for the veterinary immunobiological industry.
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Drug Discovery Landscape
2 orphan drug designations for Botulism, including 1 approved therapy.
2 orphan drug designations for Botulism, including 1 approved therapy.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
recombinant botulinum vaccine A/B | vaccines | FDA | The Surgeon General, Department of the Army | |
botulism antitoxin heptavalent (A, B, C, D, E, F, G) (Equine) | antibodies | FDA | Approved | Cangene Corporation |
“Terminated” – programs with discontinued clinical trials, or with no updates reported for 5 years after completion or 12 years after the last trial started.
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