The PD-1/PD-L1 Pathway Affects the Expansion and Function of Cytotoxic CD8(+) T Cells During an Acute Retroviral Infection

David, Paul; Megger, Dominik A.; Kaiser, Tamara; Werner, Tanja; Liu, Jia; Chen, Lieping; Sitek, Barbara; Dittmer, Ulf; Zelinskyy, Gennadiy

The kinetics of GzmB production in virus-specific CD8 + T cells were analogous to the kinetics of GzmB production in the total effector CD8 + T cell population. Frequencies of Tetramer + CD8 + T cells producing GzmB were quite similar between the groups until day 8 (Figures 2C,D) . However, at day 10 the numbers of cells producing GzmB were enhanced in the spleen and in the BM of mice deficient for PD-1 and PD-L1 in comparison to WT mice. In both organs the frequencies of GzmB + T cells was higher in the PD-L1 −/− mice than in the PD-1 −/− mice. Based on these data we propose that PD-1 regulated not only the expansion of effector cells during the early phase of FV infection, but also their differentiation into cytotoxic effectors producing GzmB.