New Murine Monoclonal Antibodies Directed against Glycophorins C and D, Have Anti-Ge2 Specificity

Background and Objectives : The Gerbich blood group system comprises three high-incidence antigens which have been localized on glycophorins C (GPC) and D (GPD) molecules. Murine monoclonal antibodies (mAbs) directed against Ge4 and Ge3 epitopes have already been obtained. We describe two murine mAbs (Z151.17 and J6) with Ge2 specificity. Materials and Methods : The mAbs were investigated by serological methods and immunoblotting, with common, Ge-negative and enzyme-modified RBCs. Results : Both mAbs behaved like anti-Ge2 in serological tests, but bound to GPC and GPD on immunoblots. Z151.17 did not recognize the GPC^Yus or GPC^Ge variants, whereas J6 revealed a 25-kD component from Ge:-2,-3,4 membranes, which is identical to the GPC^Ge molecule. Conclusion : These two mAbs are directed to slightly different epitopes. The Z151.17 and J6 epitopes are common to GPC and GPD, thus distinct from the Ge2 antigen defined by human alloantibodies.