FIGURE 8.

PD-1 deficiency allows gut-specific CD8⁺ T cells to accumulate, and acquire effector function. A, Accumulation of transferred Thy1.1⁺ PD-1^−/− OT-I T cells in lymphoid tissues and small intestines of C57BL/6 and iFABP-tOVA mice. OT-I T cell accumulation was assessed 5 days posttransfer by enumerating donor-derived (Thy1.1⁺) PD-1^−/− OT-I T cells. Values at gate indicate the percentage of OT-I T cells among total CD8⁺ cells. B, Graphic of data shown in A for lymph nodes (circles) and intestine (triangles). Data represent mean ± SD of the percentage of donor PD-1^−/− OT-I T cells among total CD8⁺ T cells. C, Absolute number of PD-1^−/− OT-I T cells in lymph nodes from data shown in B. Data represent the mean number ± SD of donor OT-I T cells per 10⁶ lymph node cells. D, Cytokine production by PD-1^−/− OT-I T cells in lymph nodes from C57BL/6 and iFABP-tOVA mice analyzed by intracellular cytokine staining and flow cytometry. For each condition, n = 3–5 individual mice were analyzed and representative contour plots are shown. Values in gate indicate the percentage of cells among CD8⁺ cells and the mean fluorescence intensity for IFN-γ or TNF-α.