title: The functional significance, distribution, and structure of LFA-1, LFA-2, and LFA-3: cell surface antigens associated with CTL-target interactions.
abstract: Three cell surface antigens associated with the cytolytic T lymphocyte(CTL)-target cell interaction were identified by generation of monoclonal antibodies (MAb) against OKT4+, HLA-DR-specific CTL and selection for inhibition of cytolysis in a 51Cr-release assay. These MAb block cytolysis by both OKT4+ and OKT8+ CTL and the proliferative responses to PHA and the mixed lymphocyte response (MLR). LFA-1 is an antigen widely distributed on lymphoid tissues and is composed of two polypeptides of 177,000 and 95,000 Mr on all cell types studied. Anti-LFA-1 MAb block NK cell-mediated cytolysis in addition to T lymphocyte-mediated cytotoxicity and proliferation. LFA-2 (Mr = 55,000 to 47,000), a determinant on the sheep red blood cell receptor, is expressed by T cells but not B cells and appears specific for T cell functions. LFA-3 (Mr = 60,000) is a widely distributed antigen present on both hematopoietic and nonhematopoietic tissues and appears to only be involved in T cell functions. MAb to LFA-1 and LFA-2 inhibit function by binding to effector cell surface molecules, whereas anti-LFA-3 MAb appear to block by binding to the target cells. Together with previously described molecules, LFA-1, LFA-2, and LFA-3 demonstrate the complexity of CTL-mediated cytotoxicity at the molecular level.
mesh_terms: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis*; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1; D010835:Phytohemagglutinins / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D016169:Lymphocyte Function-Associated Antigen-1; D010835:Phytohemagglutinins