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.
Original language | English (US) |
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Pages (from-to) | 3818-3823 |
Number of pages | 6 |
Journal | Blood |
Volume | 108 |
Issue number | 12 |
DOIs | |
State | Published - Dec 1 2006 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Immunology
- Hematology
- Cell Biology