title: CTLA-4 dysregulation of self/tumor-reactive CD8+ T-cell function is CD4+ T-cell dependent.
abstract: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) maintains peripheral tolerance by suppressing T-cell activation and proliferation but its precise role in vivo remains unclear. We sought to elucidate the impact of CTLA-4 expression on self/tumor-reactive CD8(+) T cells by using the glycoprotein (gp) 100-specific T-cell receptor (TCR) transgenic mouse, pmel-1. pmel-1 CLTA-4(-/-) mice developed profound, accelerated autoimmune vitiligo. This enhanced autoimmunity was associated with a small but highly activated CD8(+) T-cell population and large numbers of CD4(+) T cells not expressing the transgenic TCR. Adoptive transfer of pmel-1 CLTA-4(-/-) CD8(+) T cells did not mediate superior antitumor immunity in the settings of either large established tumors or tumor challenge, suggesting that the mere absence of CTLA-4-mediated inhibition on CD8(+) T cells did not directly promote enhancement of their effector functions. Removal of CD4(+) T cells by crossing the pmel-1 CLTA-4(-/-) mouse onto a Rag-1(-/-) background resulted in the complete abrogation of CD8(+) T-cell activation and autoimmune manifestations. The effects of CD4(+) CLTA-4(-/-) T cells were dependent on the absence of CTLA-4 on CD8(+) T cells. These results indicated that CD8(+) CLTA-4(-/-) T-cell-mediated autoimmunity and tumor immunity required CD4(+) T cells in which the function was dysregulated by the absence of CTLA-4-mediated negative costimulation.
authors.affiliation: Center for Cancer Research, National Cancer Institute, National Institutes of Health, Mark O. Hatfield Clinical Research Center, 10 Center Drive, Room 3-5750, Bethesda, MD 20892, USA.
authors.forename: Luca
authors.initials: L
authors.lastname: Gattinoni
authors.forename: Anju
authors.initials: A
authors.lastname: Ranganathan
authors.forename: Deborah R
authors.initials: DR
authors.lastname: Surman
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Palmer
authors.forename: Paul A
authors.initials: PA
authors.lastname: Antony
authors.forename: Marc R
authors.initials: MR
authors.lastname: Theoret
authors.forename: David M
authors.initials: DM
authors.lastname: Heimann
authors.forename: Steven A
authors.initials: SA
authors.lastname: Rosenberg
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Restifo
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D000943:Antigens, Differentiation / Q000235:genetics / Q000276:immunology*; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology; D015551:Autoimmunity / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D060908:CTLA-4 Antigen; D049109:Cell Proliferation; D018398:Homeodomain Proteins / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D008212:Lymphocyte Depletion / Q000379:methods; D051379:Mice; D018345:Mice, Knockout; D009369:Neoplasms / Q000235:genetics / Q000276:immunology*; D014820:Vitiligo / Q000235:genetics / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D018398:Homeodomain Proteins; C064658:RAG-1 protein