Keyhole limpet hemocyanin contains Gal(?1-3)-GalNAc determinants that are cross-reactive with the T-antigen

Keyhole limpet hemocyanin (KLH) is widely used as a carrier molecule to enhance immune responses to administered antigens, and for immunotherapy of bladder and renal carcinoma. In the present study we show, using lectin and antibody binding studies, that native KLH contains Gal(beta 1-3)GalNAc-bearing oligosaccharides, and that immunization with KLH in Lewis rats induces the production of anti-Gal(beta 1-3) GalNAc antibodies. This might explain the beneficial effect of KLH in bladder cancers that express cross-reactive Gal(beta 1-3)GalNAc determinants or the T antigen.