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

Our current characterization of antiviral CTL responses in PD-1 −/− and PD-L1 −/− mice suggests a suppressive effect FIGURE 3 | Production of different granzymes in CD8 + T cells from PD-L1 −/− mice. C57BL/6 (white columns) and PD-L1 −/− (black columns) mice were infected with FV and splenocytes were isolated at 8, 10, and 12 days after infection. Flow cytometry was used to detect intracellular expression of GzmA, GzmB, and GzmK in effector CD8 + T cells (CD43 + ) and in CD8 + T cells specific for the FV gagL epitope (Tetramer + ) from the spleen. The analysis was performed at day 8, 10, and 12 after FV infection. Shown are the numbers of all effector CD43 + CD8 + T cells (A-C) and virus-specific Tetramer+CD8 + (D-F) expressing single, double, or all three granzymes together. Each dot represents an individual mouse and the mean numbers and SD are indicated. Data were pooled from two independent experiments with similar results. Differences were analyzed by unpaired t-test (*p < 0.05, **p < 0.005, ***p < 0.0005).