title: The accessory function of murine intercellular adhesion molecule-1 in T lymphocyte activation. Contributions of adhesion and co-activation.
abstract: These studies demonstrate that the murine intercellular adhesion molecule-1 (ICAM-1) performs at least two roles in enhancing T cell activation. These two roles are evident in both of our experimental systems: with ICAM-1 expressed on the surface of transfected fibroblast cells, and with purified ICAM-1 immobilized on plastic. First, as has been documented by many investigators, ICAM-1 mediates adhesion between ICAM-1- and lymphocyte function-associated Ag-1 (LFA-1)-bearing cells. This adhesive interaction occurs even in the absence of T cell stimulation, although it is increased by addition of phorbol ester and calcium ionophore. Although ICAM-1 expression does markedly increase intercellular adhesion, the increase is significantly less than the improvement ICAM-1 expression makes in the Ag-presenting ability of MHC class II-transfected fibroblast cells. We have investigated whether this difference is due to LFA-1-mediated signaling, and we present data that demonstrates that although ICAM-1 does not deliver costimulatory signals required for T cell activation, the interaction of LFA-1 with ICAM-1 does synergize with TCR-transduced signals. This synergy is observed for ICAM-1 on live and on chemically fixed accessory cells, and for purified ICAM-1 molecules, but in all cases occurs only when the ICAM-1 and the TCR ligands are on the same surface. Finally, when the ICAM-1 is present on the surface of accessory cells, it enhances T cell activation by changing the Ag dose-dependence of the T cell, but when ICAM-1 and CD3 mAb are co-immobilized, ICAM-1 increases the peak response of the T cell without affecting the dose dependence of the response.
authors.affiliation: Department of Chemistry, University of California, San Diego, La Jolla 92093-0063.
authors.forename: P
authors.initials: P
authors.lastname: Kuhlman
authors.forename: V T
authors.initials: VT
authors.lastname: Moy
authors.forename: B A
authors.initials: BA
authors.lastname: Lollo
authors.forename: A A
authors.initials: AA
authors.lastname: Brian
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000938:Antigen-Presenting Cells / Q000166:cytology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D001483:Base Sequence; D017252:CD3 Complex; D002448:Cell Adhesion / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000502:physiology*; D005347:Fibroblasts / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000502:physiology; D018799:Intercellular Adhesion Molecule-1; D008213:Lymphocyte Activation / Q000502:physiology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology*; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015815:Cell Adhesion Molecules; D000949:Histocompatibility Antigens Class II; D016169:Lymphocyte Function-Associated Antigen-1; D011948:Receptors, Antigen, T-Cell; D018799:Intercellular Adhesion Molecule-1