Phenotype, Function and Gene Expression Profiles of PD-1 high CD8 T cells in Healthy Human Adults

T cell dysfunction is an important feature of many chronic viral infections. In particular, it was shown that PD-1 regulates T cell dysfunction during chronic LCMV infection in mice and PD-1 high cells exhibit an intense exhausted gene signature. These findings were extended to human chronic infections such as HIV, HCV and HBV. However, it is not known if PD-1 high cells of healthy humans have the traits of exhausted cells. In this study, we provide a comprehensive description of phenotype, function and gene expression profiles of PD-1 high versus PD-1 low CD8 T cells in the peripheral blood of healthy human adults as following: 1) The percentage of naive and memory CD8 T cells varied widely in the peripheral blood cells of healthy humans and PD-1 was expressed by the memory CD8 T cells. 2) PD-1 high CD8 T cells in healthy humans did not significantly correlated with the PD-1 high exhausted gene signature of HIV specific human CD8 T cells or chronic LCMV specific CD8 T cells from mice. 3) PD-1 expression did not directly affect the ability of CD8 T cells to secrete cytokines in healthy adults. 4) PD-1 was expressed by the effector memory (TEM) compared to terminally differentiated effector (TEMRA) CD8 T cells. 5) Finally, an interesting inverse relationship between CD45RA and PD-1 expression was observed.

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Duraiswamy J, Ibegbu CC, Masopust D, Miller JD, Araki K, Doho GH, Tata P, Gupta S, Zilliox MJ, Nakaya HI, Pulendran B, Haining WN, Freeman GJ, Ahmed R