title: Analysis of the costimulatory requirements for generating human virus-specific in vitro T helper and effector responses.
abstract: The present study analyzes the role of CD28-B7-mediated costimulation during in vitro human peripheral blood memory T cell activation by influenza A virus. Inhibition studies using the B7-binding fusion protein CTLA4Ig and antibodies against CD80 and CD86 demonstrate that CTLA4Ig and anti-CD86 inhibited influenza-specific T cell proliferation, interleukin (IL)-2 and interferon (IFN)-gamma production, and generation of influenza-specific CD8+ CTL. The production of IL-10 and IL-18, which are known to modulate T cell immune responses, were not affected by blocking the CD28-B7 costimulatory pathway. Inhibition of diverse influenza-specific T cell functions could be reversed by the addition of exogenous IL-2 or IL-12 but not by the addition of IFN-gamma or IL-18. Although IL-2 is known to overcome CD28-B7 costimulatory requirements, this is the first report showing that exogenous IL-12 is able to bypass CD28-B7 costimulatory blockade induced by CTLA4Ig in vitro. The induction of IFN-gamma production with the recently described IFN-gamma inducing cytokine IL-18 was not detected. In conclusion, these results demonstrate that CD86 represents a major costimulatory signal for the activation of resting peripheral blood memory T cells with recall antigens. These observations may have important implications for the development of immunotherapeutic strategies in diverse immunodeficiency diseases as well as in tumor immunotherapy.
authors.affiliation: Experimental Immunology Branch, National Cancer Institute, National Institute of Health, Bethesda, Maryland, USA. ltvebl@uta.fi
authors.forename: V
authors.initials: V
authors.lastname: Blazevic
authors.forename: C M
authors.initials: CM
authors.lastname: Trubey
authors.forename: G M
authors.initials: GM
authors.lastname: Shearer
mesh_terms: D000069594:Abatacept; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000938:Antigen-Presenting Cells / Q000276:immunology; D015703:Antigens, CD / Q000378:metabolism; D000943:Antigens, Differentiation / Q000494:pharmacology; D018122:B7-1 Antigen / Q000378:metabolism; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000378:metabolism; D060908:CTLA-4 Antigen; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D007108:Immune Tolerance; D018796:Immunoconjugates; D007156:Immunologic Memory; D066298:In Vitro Techniques; D009980:Influenza A virus / Q000276:immunology*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497964:CD86 protein, human; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D016207:Cytokines; D018796:Immunoconjugates; D008562:Membrane Glycoproteins; D000069594:Abatacept