title: HLA-DC antigens can serve as recognition elements for human cytotoxic T lymphocytes.
abstract: The specificity of four cytotoxic T lymphocyte (CTL) clones which recognize class II major histocompatibility complex (MHC) antigens was analyzed. All clones recognized antigens associated with the serologically defined HLA-DRw6 specificity. The activity of two of these clones, JR-2-2 and JR-2-10, could be inhibited by a monoclonal antibody Q 5/13 specific for a monomorphic determinant present on HLA-DR. In contrast, the activity of the two other CTL clones, JR-2-19 and JR-2-26, was not blocked by Q 5/13, but by a new monoclonal reagent, SPV-L3. This latter monoclonal antibody precipitated a two-chain structure of 28 kDa and 33 kDa and reacts with a monomorphic determinant. The molecular weight of the polypeptides precipitated with SPV-L3 was slightly less than those precipitated with a HLA-DR-specific monoclonal reagent. In addition two-dimensional gel electrophoresis showed that the antigen precipitated by SPV-L3 differed in charge from those precipitated with the anti-HLA-DR antibody. These results indicate that SPV-L3 recognizes a class II MHC product different from HLA-DR. This observation was confirmed by partial amino acid sequence analysis of the two chains which revealed that the molecule precipitated by SPV-L3 is homologous to HLA-DC/DS molecules. Therefore this report provides the first evidence that human cytotoxic T cells can recognize HLA-DC/DS antigens.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D002999:Clone Cells; D004591:Electrophoresis, Polyacrylamide Gel; D006683:HLA-DQ Antigens; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D007106:Immune Sera; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000276:immunology; D011817:Rabbits / Q000276:immunology; D012967:Sodium Dodecyl Sulfate; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D006683:HLA-DQ Antigens; D000949:Histocompatibility Antigens Class II; D007106:Immune Sera; D010835:Phytohemagglutinins; D012967:Sodium Dodecyl Sulfate