Nontoxic, multi-domain botulinum neurotoxin-LCHCN as vaccines against botulism.
Year: 2025
Type: article
Abstract: Botulinum neurotoxins (BoNTs), the causative agents of botulism, are proteins consisting of an N-terminal catalytic Light Chain (LC) and a C-terminal Heavy Chain (HC), which comprises a LC-translocation domain (HC N ) and a receptor binding domain (HC C ). There are seven BoNT serotypes (A-G) and multiple subtypes. Currently, there is no approved vaccine against botulism available for human use. Several studies have investigated BoNT domains, multi-domains, or mutated holotoxins as candidate BoNT vaccines. However, residual toxicity has been observed in mutated full-length BoNTs and multi-domain (LCHC N ) vaccines. In this study, six-individual point substitutions (6M) were introduced into the substrate binding and cleavage sites, zinc binding motif, and LC translocation region of LCHC N /A1 and LCHC N /B1, which possessed no detectable toxicity in mice at 200 μg, being >40-million-fold less toxic than full-length BoNT. IP immunization of mice with 6MLCHC N /A1 or 6MLCHC N /B1 elicited a strong IgG response that protected against high dose challenge with BoNT/A1 or BoNT/B1, respectively. 4MBoNT/B1 and 7MBoNT/B1 were also engineered and found to elicit strong IgG responses that protected against high dose challenge with BoNT/B1. Thus, multi-domain inactivation may yield potent and safe vaccines against other BoNT-serotypes and BoNT-like proteins. The strategy of systematic inactivation of multiple functional domains by targeted single amino acid substitutions to decrease toxicity, combined with investigations of the most immunogenic and protective domains, provides a robust platform for protein toxin vaccines for humans and animals. • 6MLCHC N /A1 or 6MLCHC N /B1 vaccines lack the neuronal receptor-binding domain and inactivate LC function and translocation. • Two hundred μg of single- or di-chain- 6MLCHCN/A1 or 6MLCHCN/B1 were nontoxic in mice, being >40-million-fold less toxic than native botulinum toxins. • Immunization of mice with sub-μg 6MLCHC N /A1 and 6MLCHC N /B1 neutralized challenge by 10 5 LDs of BoNT/A1 and BoNT/B1. • 6MLCHC N /A1 and 6MLCHC N /B1 were strong protective immunogens similar to full-length 7 M BoNT/B1 or 4 M BoNT/A1 vaccines. • LCHC N vaccines are not classified as Select Agents and constitute safe vaccine candidates.
Source: Vaccine
Authors: A. Przedpelski, W.H. Tepp, S. Gupta, J.T. Barbieri, S. Pellett
Institutions: Medical College of Wisconsin, University of Wisconsin–Madison
Language: English
Subfield: Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,620
Awards: G869137369, Vaccines Against Botulism
OpenAlex ID: W4414522319