title: CD81 expressed on human thymocytes mediates integrin activation and interleukin 2-dependent proliferation.
abstract: Lymphocyte recognition of antigen by the antigen-specific T cell receptor (TCR) and coreceptor complexes rapidly alters the cell's adhesive properties facilitating high avidity cell-ligand interactions necessary for lymphocyte development and function. Here, we report the expression of CD81 (target of antiproliferative antigen [TAPA]-1) on human thymocytes and the physical association of CD81 with CD4 and CD8 T cell coreceptors. Antibody ligation of CD81 on thymocytes promotes the rapid induction of integrin-mediated cell-cell adhesion via lymphocyte function-associated molecule-1 (LFA-1). Cross-linking CD81 is also shown to be costimulatory with signaling through the TCR/CD3 complex inducing interleukin 2-dependent thymocyte proliferation. These data suggest that a CD81-mediated pathway in thymocytes is involved in the regulation of both cell adhesion and activation.
authors.affiliation: Department of Biology and Molecular Biology Institute, San Diego State University, California 92182-4614, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: Todd
authors.forename: S G
authors.initials: SG
authors.lastname: Lipps
authors.forename: L
authors.initials: L
authors.lastname: Crisa
authors.forename: D R
authors.initials: DR
authors.lastname: Salomon
authors.forename: C D
authors.initials: CD
authors.lastname: Tsoukas
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D015704:CD4 Antigens / Q000378:metabolism; D016827:CD8 Antigens / Q000378:metabolism; D002448:Cell Adhesion; D003432:Cross-Linking Reagents; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism*; D008565:Membrane Proteins; D011485:Protein Binding; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D060225:Tetraspanin 28; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
chemical_list: D015703:Antigens, CD; D015704:CD4 Antigens; D016827:CD8 Antigens; C554798:CD81 protein, human; D003432:Cross-Linking Reagents; D007376:Interleukin-2; D016169:Lymphocyte Function-Associated Antigen-1; D008565:Membrane Proteins; D060225:Tetraspanin 28