Epitopes described in "Molecular evolution of antibody cross-reactivity for two subtypes of type A botulinum neurotoxin."

Article Authors:Consuelo Garcia-Rodriguez; Raphael Levy; Joseph W Arndt; Charles M Forsyth; Ali Razai; Jianlong Lou; Isin Geren; Raymond C Stevens; James D Marks
Article Title:Molecular evolution of antibody cross-reactivity for two subtypes of type A botulinum neurotoxin.
Reference Detail
Reference ID:1004997
Abstract:Broadening antibody specificity without compromising affinity should facilitate detection and neutralization of toxin and viral subtypes. We used yeast display and a co-selection strategy to increase cross-reactivity of a single chain (sc) Fv antibody to botulinum neurotoxin type A (BoNT/A). Starting with a scFv that binds the BoNT/A1 subtype with high affinity (136 pM) and the BoNT/A2 subtype with low affinity (109 nM), we increased its affinity for BoNT/A2 1,250-fold, to 87 pM, while maintaining high-affinity binding to BoNT/A1 (115 pM). To find the molecular basis for improved cross-reactivity, we determined the X-ray co-crystal structures of wild-type and cross-reactive antibodies complexed to BoNT/A1 at resolutions up to 2.6 A, and measured the thermodynamic contribution of BoNT/A1 and A2 amino acids to wild-type and cross-reactive antibody binding. The results show how an antibody can be engineered to bind two different antigens despite structural differences in the antigen-antibody interface and may provide a general strategy for tuning antibody specificity and cross-reactivity.
Affiliations:Department of Anesthesia and Pharmaceutical Chemistry, University of California, San Francisco Rm. 3C-38, San Francisco General Hospital, 1001 Potrero Ave., San Francisco, California 94110, USA.
Reference Type:Literature
PubMed ID:17173035
Journal:Nat Biotechnol
Journal Volume:25
Article Pages:107-16
Journal ISSN:1087-0156
Article Chemical List:Antibodies, Monoclonal;Botulinum Toxins, Type A
Article MeSH List:Antibodies, Monoclonal(genetics; immunology; metabolism); Binding Sites; Botulinum Toxins, Type A(immunology; metabolism); Drug Design; Epitope Mapping(methods); Protein Binding; Protein Engineering(methods); Protein Interaction Mapping(methods)
Curation Last Updated:2015-05-05 19:52:39