title: The tetraspanin CD9 is preferentially expressed on the human CD4(+)CD45RA+ naive T cell population and is involved in T cell activation.
abstract: Human CD4+ T cells can be divided into reciprocal memory and naive T cell subsets based on their expression of CD45 isoforms and CD29/integrin beta1 subunit. To identify unique cell surface molecules on human T cells, we developed a new monoclonal antibody termed anti5H9. Binding of anti5H9 triggers a co-stimulatory response in human peripheral blood T cells. Retrovirus-mediated expression cloning has revealed that the antigen recognized by anti5H9 is identical to the tetraspanin CD9. We now show that human CD9 is preferentially expressed on the CD4(+)CD45RA+ naive T cell subset, and that CD9(+)CD45RA+ T cells respond preferentially to the recombinant beta2-glycoprotein I, compared to CD9-CD45RA+ T cells. Furthermore, anti5H9 inhibits both the recombinant beta2-glycoprotein I- and the recall antigen tetanus toxoid-specific T cell proliferation. These results suggest that the tetraspanin CD9 plays an important role in T cell activation.
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: O
authors.initials: O
authors.lastname: Hosono
authors.forename: S
authors.initials: S
authors.lastname: Iwata
authors.forename: H
authors.initials: H
authors.lastname: Kawasaki
authors.forename: M
authors.initials: M
authors.lastname: Kuwana
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: N H
authors.initials: NH
authors.lastname: Dang
authors.forename: C
authors.initials: C
authors.lastname: Morimoto
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000925:Anticoagulants / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D017493:Leukocyte Common Antigens / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013745:Tetanus Toxoid / Q000276:immunology; D060245:Tetraspanin 29; D053482:beta 2-Glycoprotein I
chemical_list: D000911:Antibodies, Monoclonal; D000925:Anticoagulants; D015703:Antigens, CD; D015704:CD4 Antigens; C554869:CD9 protein, human; C554870:Cd9 protein, mouse; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D013745:Tetanus Toxoid; D060245:Tetraspanin 29; D053482:beta 2-Glycoprotein I; D017493:Leukocyte Common Antigens