title: Crosslinking CD81 results in activation of TCRgammadelta T cells.
abstract: CD81 is expressed on most cells and is associated with other glycoproteins, including CD4 and CD8, to form multimolecular membrane complexes. Crosslinking of CD81 on TCRalphabeta(+) T cells results in costimulatory signals that have been proposed to be mediated via CD4 or CD8. In this study, we show that CD81 is also expressed on TCRgammadelta(+)CD4(-)CD8(-) T cells. CD81 crosslinking greatly enhanced anti-CD3 activation of both TCRalphabeta(+) (CD4+ and CD8+) and TCRgammadelta(+) T cells with regard to IFN-gamma production. However, crosslinking of CD81 molecules on TCRgammadelta(+) T cells, in the absence of anti-CD3 stimulation, resulted in cytokine production and enhanced IL-2-induced proliferation, demonstrating that physical association with CD4 or CD8 is not necessary for CD81 signaling. In contrast, crosslinking of CD81 on TCRalphabeta(+) T cells, in the absence of anti-CD3 stimulation, failed to activate these T cells. These results suggest that CD81 signaling may be mediated via a different mechanism(s) in TCRgammadelta(+) versus TCRalphabeta(+) T cells.
authors.affiliation: Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA.
authors.forename: C T
authors.initials: CT
authors.lastname: Tseng
authors.forename: E
authors.initials: E
authors.lastname: Miskovsky
authors.forename: G R
authors.initials: GR
authors.lastname: Klimpel
mesh_terms: D015703:Antigens, CD / Q000276:immunology*; D017252:CD3 Complex / Q000276:immunology; D002455:Cell Division; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology*; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D008565:Membrane Proteins; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D060225:Tetraspanin 28
chemical_list: D015703:Antigens, CD; D017252:CD3 Complex; C554798:CD81 protein, human; D007376:Interleukin-2; D008565:Membrane Proteins; D016692:Receptors, Antigen, T-Cell, gamma-delta; D060225:Tetraspanin 28; D007371:Interferon-gamma