title: HLA-A2 peptides can regulate cytolysis by human allogeneic T lymphocytes.
abstract: The class-I and class-II molecules encoded by the major histocompatibility complex (MHC) are homologous proteins which allow cytotoxic and helper T cells to recognize foreign antigens. Recent studies have shown that the form of the antigen recognized by T cells is generally not a native protein but rather a short peptide fragment and that class-II molecules specifically bind antigenic peptides. Furthermore, the three-dimensional structure of the human MHC class-I molecule, HLA-A2, is consistent with a peptide-binding function for MHC class-I molecules. An outstanding question concerns the molecular nature and involvement of MHC-bound peptides in antigens recognized by alloreactive T cells. In this study the effects of peptides derived from HLA-A2 on cytolysis of alloreactive cytotoxic T cells (TC) cells are presented. Peptides can inhibit lysis by binding to the T cell or sensitize to lysis by binding an HLA-A2-related class-I molecule (HLA-Aw69) on the target cell. Thus, allospecific TC cells can recognize HLA-derived peptides in the context of the MHC.
mesh_terms: D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D006680:HLA Antigens / Q000502:physiology*; D015789:HLA-A2 Antigen; D006801:Humans; D010446:Peptide Fragments / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D006680:HLA Antigens; D015789:HLA-A2 Antigen; D010446:Peptide Fragments