Engagement of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) induces transforming growth factor beta (TGF-beta) production by murine CD4(+) T cells.
Evidence indicates that cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) may negatively regulate T cell activation, but the basis for the inhibitory effect remains unknown. We report here that cross-linking of CTLA-4 induces transforming growth factor beta (TGF-beta) production by murine CD4(+) T cells. CD4(+) T helper type 1 (Th1), Th2, and Th0 clones all secrete TGF-beta after antibody cross-linking of CTLA-4, indicating that induction of TGF-beta by CTLA-4 signaling represents a ubiquitous feature of murine CD4(+) T cells. Stimulation of the CD3-T cell antigen receptor complex does not independently induce TGF-beta, but is required for optimal CTLA-4-mediated TGF-beta production. The consequences of cross-linking of CTLA-4, together with CD3 and CD28, include inhibition of T cell proliferation and interleukin (IL)-2 secretion, as well as suppression of both interferon gamma (Th1) and IL-4 (Th2). Moreover, addition of anti-TGF-beta partially reverses this T cell suppression. When CTLA-4 was cross-linked in T cell populations from TGF-beta1 gene-deleted (TGF-beta1(-/-)) mice, the T cell responses were only suppressed 38% compared with 95% in wild-type mice. Our data demonstrate that engagement of CTLA-4 leads to CD4(+) T cell production of TGF-beta, which, in part, contributes to the downregulation of T cell activation. CTLA-4, through TGF-beta, may serve as a counterbalance for CD28 costimulation of IL-2 and CD4(+) T cell activation.
Chen
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Oral Infection and Immunity Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
Jin
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Wahl
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D000069594:Abatacept; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000378:metabolism*; D017209:Apoptosis / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D060908:CTLA-4 Antigen; D002455:Cell Division / Q000276:immunology; D002470:Cell Survival / Q000276:immunology; D003432:Cross-Linking Reagents / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D018796:Immunoconjugates; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D010047:Ovalbumin / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism
D015703:Antigens, CD; D000943:Antigens, Differentiation; D018106:CD28 Antigens; D017252:CD3 Complex; D060908:CTLA-4 Antigen; D003432:Cross-Linking Reagents; C556707:Ctla4 protein, mouse; D016207:Cytokines; D018796:Immunoconjugates; D011948:Receptors, Antigen, T-Cell; D016212:Transforming Growth Factor beta; D000069594:Abatacept; D010047:Ovalbumin