Enhanced binding to antigen of monoclonal antibodies modified with a crosslinker.

Modification of monoclonal antibodies (mAbs) with a photo-crosslinker, sulfosuccinimidyl 2-(m-azido-o-nitrobenzamido)-ethyl-1, 3'-dithiopropionate (SAND), enhanced their antigen binding activity. By SAND modification, SV2-61 gamma mAb against human c-erbB-2 protooncogene product could immunoprecipitate approximately an 8-fold greater amount of antigen, and AB-3 mAb against bovine serum albumin (BSA) bound to BSA more efficiently than unmodified mAb as determined by an enzyme-linked immunosorbent assay. Relative binding affinity of SAND-modified AB-3 was about 4-fold of unmodified AB-3. Augmented binding of mAbs was observed with or without photosensitization.