Antibody dependent cellular cytotoxicity mediated by HLA-class II specific monoclonal antibodies.

The ability of mouse monoclonal antibodies (MoAbs) directed against HLA-class II molecules to mediate in Antibody Dependent Cellular Cytotoxicity (ADCC) was investigated. The results indicate that both MoAbs to monomorphic and polymorphic HLA-DR and DQ determinants are able to mediate ADCC in an antigen specific manner. However, not all antibodies mediate ADCC to a similar extent. Furthermore, antibodies were identified that appeared to mediate ADCC in an HLA-DR haplotype dependent fashion. These results indicate that the inhibition of HLA-class II specific proliferative responses by anti-class II MoAbs may be influenced by ADCC directed against class II positive stimulator cells.