1. A Three-Monoclonal Antibody Combination Potently Neutralizes BoNT/G Toxin in Mice
- Author
-
Fan, Yongfeng, Lou, Jianlong, Tam, Christina C, Wen, Weihua, Conrad, Fraser, da Silva Alves, Priscila Leal, Cheng, Luisa W, Garcia-Rodriguez, Consuelo, Farr-Jones, Shauna, and Marks, James D
- Subjects
Pharmacology and Pharmaceutical Sciences ,Biomedical and Clinical Sciences ,Emerging Infectious Diseases ,Biotechnology ,Prevention ,Foodborne Illness ,Infectious Diseases ,Biodefense ,Vaccine Related ,Immunization ,Rare Diseases ,Mice ,Animals ,Horses ,Antibodies ,Monoclonal ,Botulism ,Botulinum Toxins ,Type A ,Single-Chain Antibodies ,Antitoxins ,Saccharomyces cerevisiae ,Immunoglobulin G ,botulinum neurotoxin ,oligoclonal antibodies ,serotype G botulism ,recombinant antibodies ,antibody engineering ,mouse neutralization assay ,Biochemistry and Cell Biology ,Pharmacology and pharmaceutical sciences - Abstract
Equine-derived antitoxin (BAT®) is the only treatment for botulism from botulinum neurotoxin serotype G (BoNT/G). BAT® is a foreign protein with potentially severe adverse effects and is not renewable. To develop a safe, more potent, and renewable antitoxin, humanized monoclonal antibodies (mAbs) were generated. Yeast displayed single chain Fv (scFv) libraries were prepared from mice immunized with BoNT/G and BoNT/G domains and screened with BoNT/G using fluorescence-activated cell sorting (FACS). Fourteen scFv-binding BoNT/G were isolated with KD values ranging from 3.86 nM to 103 nM (median KD 20.9 nM). Five mAb-binding non-overlapping epitopes were humanized and affinity matured to create antibodies hu6G6.2, hu6G7.2, hu6G9.1, hu6G10, and hu6G11.2, with IgG KD values ranging from 51 pM to 8 pM. Three IgG combinations completely protected mice challenged with 10,000 LD50s of BoNT/G at a total mAb dose of 6.25 μg per mouse. The mAb combinations have the potential for use in the diagnosis and treatment of botulism due to serotype G and, along with antibody combinations to BoNT/A, B, C, D, E, and F, provide the basis for a fully recombinant heptavalent botulinum antitoxin to replace the legacy equine product.
- Published
- 2023