A Novel Botulinum Toxin, Previously Reported as Serotype H, has a Hybrid Structure of Known Serotypes A and F that is Neutralized with Serotype A Antitoxin.

Maslanka SE1, Lúquez C2, Dykes JK2, Tepp WH3, Pier CL3, Pellett S3, Raphael BH2, Kalb SR2, Barr JR2, Rao A2, Johnson EA3.

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Abstract

Botulism is a potentially fatal paralytic disease caused by the action of botulinum neurotoxin (BoNT) on nerve cells. There are 7 known serotypes (A through G) of BoNT and up to 40 genetic variants. Clostridium botulinum strain IBCA10-7060 was recently reported to produce BoNT serotype B (BoNT/B) and a novel BoNT, designated by the authors as BoNT/H. The botulinum neurotoxin gene (bont) sequence of BoNT/H was analyzed against known related bont sequences. Genetic analysis suggested that BoNT/H has a hybrid-like structure containing regions of similarity to BoNT/A1 and /F5. This novel BoNT was serologically characterized by the mouse neutralization assay and a neuronal cell-based assay. The toxic effects of this hybrid-like BoNT were completely eliminated by existing serotype A antitoxin including those contained in multivalent therapeutic antitoxin products that are the mainstay for human botulism treatment.

Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.