The tetraspanin CD9 is preferentially expressed on the human CD4(+)CD45RA+ naive T cell population and is involved in T cell activation

Clin Exp Immunol. 2004 Jul;137(1):101-8. doi: 10.1111/j.1365-2249.2004.02494.x.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology*
  • Anticoagulants / immunology
  • Antigens, CD / immunology*
  • CD4 Antigens / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • Cells, Cultured
  • Glycoproteins / immunology
  • Humans
  • Leukocyte Common Antigens / immunology*
  • Lymphocyte Activation / immunology
  • Membrane Glycoproteins / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Recombinant Proteins / immunology
  • T-Lymphocyte Subsets / immunology*
  • Tetanus Toxoid / immunology
  • Tetraspanin 29
  • beta 2-Glycoprotein I


  • Antibodies, Monoclonal
  • Anticoagulants
  • Antigens, CD
  • CD4 Antigens
  • CD9 protein, human
  • Cd9 protein, mouse
  • Glycoproteins
  • Membrane Glycoproteins
  • Recombinant Proteins
  • Tetanus Toxoid
  • Tetraspanin 29
  • beta 2-Glycoprotein I
  • Leukocyte Common Antigens