TIGIT expression on CD8+ T cells correlates with higher cytotoxic capacity

Persistent exposure to antigen leads to T cell exhaustion and immunologic dysfunction. We examined the immune exhaustion markers TIGIT and PD-1 in HIV-infected and healthy individuals and the relationship with cytotoxic CD8+ T lymphocyte (CTL) activity. Frequencies of TIGIT but not PD-1 positively correlated with CTL activity in HIV-aviremic and healthy individuals; however, there was no correlation in HIV-viremic individuals. Transcriptome analyses revealed upregulation of genes associated with antiviral immunity in TIGIT+ versus TIGIT-CD8+ T cells. Our data suggest that TIGIT+CD8+ T cells do not necessarily represent a state of immune exhaustion and maintain an intrinsic cytotoxicity in HIV-infected individuals. 29 total patients, with 8 aviremic, 6 viremic, and 15 negative. For each patients, expression was measured in CD8+ T-cells, both TIGIT+ and TIGIT-