Location and reduction of icarapin antigenicity by site specific coupling to polyethylene glycol.

Icarapin is a bee venom protein found to induce IgE-mediated allergic reaction. In this study, icarapin of Asian honey bee was cloned and sequenced. By in silico screening, S198 was found to be the potential antigenic site. This site was changed to cysteine and coupled with PEG5K. Compared to the wild type icarapin and the S198C variant, PEGylated S198C variant induced lower level of IgG and IgE antibodies in mice, showing that it is indeed located in an antigenic site. Our work may be generalized to other proteins for the discovery of antigenic sites and the reduction of antigenicity.