Correlation Between TIGIT Expression on CD8+ T Cells and Higher Cytotoxic Capacity

Persistent exposure to antigen leads to T-cell exhaustion and immunologic dysfunction. We examined the immune exhaustion markers T cell immunoglobulin and ITIM domain (TIGIT) and programmed cell death protein 1 (PD-1) in human immunodeficiency virus (HIV)-infected and healthy individuals and the relationship with cytotoxic CD8(+) T-lymphocyte activity. Frequencies of TIGIT but not PD-1 were positively correlated with CD8(+) T-lymphocyte activity in HIV-aviremic and healthy individuals; however, there was no correlation in HIV-viremic individuals. Transcriptome analyses revealed up-regulation of genes associated with antiviral immunity in TIGIT(+)CD8(+) 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.

Automated summary

The study found that levels of TIGIT were positively correlated with CD8(+) T-lymphocyte activity in HIV-infected and healthy individuals, but not in HIV-viremic individuals. Furthermore, TIGIT(+)CD8(+) T cells maintained intrinsic cytotoxicity in HIV-infected individuals, suggesting they may not represent a state of immune exhaustion.