Identification of a Human Monoclonal Antibody to Replace Equine Diphtheria Anti-toxin for the Treatment of Diphtheria
Authors
Sevigny, Leila M.Booth, Brian J.
Rowley, Kirk J.
Leav, Brett A.
Cheslock, Peter S.
Garrity, Kerry A.
Sloan, Susan
Babcock, Gregory J.
Thomas, William D.
Klempner, Mark
Wang, Yang
Document Type
Poster AbstractPublication Date
2013-05-08Keywords
Amino Acids, Peptides, and ProteinsBacterial Infections and Mycoses
Immunoprophylaxis and Therapy
Translational Medical Research
Metadata
Show full item recordAbstract
Diphtheria anti-toxin (DAT) has been used to treat Corynebacterium diphtheriae infection for over one hundred years. While the global incidence of diphtheria has declined in the 20th century, the disease remains endemic in many parts of the world and significant outbreaks still occur. Diphtheria anti-toxin is an equine polyclonal antibody with considerable side effects that is in critically short supply globally. A safer, more readily available alternative to DAT would be desirable. In the current study, we cloned human monoclonal antibodies (HuMabs) directly from antibody secreting cells of human volunteers immunized with Td vaccine. We isolated a diverse panel of HuMabs that recognized diphtheria toxoid and recombinant protein fragments of diphtheria toxin. Forty-one unique HuMabs were expressed in 293T cells and tested for neutralization of diphtheria toxin in in vitro cytotoxicity assays. The lead candidate HuMab, 315C4 potently neutralized diphtheria toxin with an EC50 of 0.65 ng/mL. Additionally, 25 μg of 315C4 completely protected guinea pigs in an in vivo lethality model. In comparison, 1.6 IU of DAT was necessary for full protection resulting in an estimated relative potency of 64 IU/mg for 315C4. We further established that our lead candidate HuMab binds to the receptor binding domain of diphtheria toxin and blocks the toxin from binding to the putative receptor, heparin binding-epidermal growth factor like growth factor. The discovery of a specific and potent neutralizing antibody against diphtheria toxin holds promise as a potential human therapeutic and is being developed for human use.DOI
10.13028/hy06-8p85Permanent Link to this Item
http://hdl.handle.net/20.500.14038/27789Rights
Copyright the Author(s)Distribution License
http://creativecommons.org/licenses/by-nc-sa/3.0/ae974a485f413a2113503eed53cd6c53
10.13028/hy06-8p85