title: Functional evidence that intercellular adhesion molecule-1 (ICAM-1) is a ligand for LFA-1-dependent adhesion in T cell-mediated cytotoxicity.
abstract: Although intercellular adhesion molecule-1 (ICAM-1) has been implicated as a ligand in some LFA-1-dependent adhesion, its importance to T cell function has not been established. The present studies investigate the importance of ICAM-1 for human cytotoxic T lymphocytes (CTL), both in their formation of antigen-independent conjugates (AIC) and in their lysis of targets. Analysis of monoclonal antibody (mAb) inhibition of AIC formation indicate that ICAM-1 mAb 1 blocks (a) AIC formation with some but not all targets; (b) the LFA-1 pathway but not the CD2/LFA-3 pathway of adhesion; (c) by binding to the target cell, not the T cell. In studies of cell-mediated lysis (CML) ICAM-1 mAb inhibited lysis of some targets, such as U-937, that use ICAM-1 predominantly in AIC formation; CML on some other targets is not inhibited by ICAM-1 mAb. These data indicate that ICAM-1 is a ligand for AIC formation, antigen-specific CTL recognition and cytolysis of particular target cells. The data also indicate that ICAM-1 is not used in LFA-1-dependent CTL interactions with all kinds of target cells, suggesting the existence of alternative ligands for LFA-1.
mesh_terms: D000911:Antibodies, Monoclonal; D000941:Antigens / Q000276:immunology; D000954:Antigens, Surface / Q000502:physiology*; D018821:CD18 Antigens; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007111:Immunity, Cellular; D007158:Immunologic Techniques; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1; D008562:Membrane Glycoproteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D000954:Antigens, Surface; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1; D008562:Membrane Glycoproteins