Phenotype and function of virus-specific CD8⁺ T cells in tissues of LCMV infected CIITA^Tg mice.

<p>(<b>A-C</b>) Lymphocytes were isolated from the spleen and lungs of LCMV CL–13 (5 x 10⁵ PFU per mouse) infected wild-type and CIITA^Tg mice at 31 DPI and analyzed by flow cytometry. Total numbers of GP33 and GP_276-286 (GP276) tetramer-positive CD8⁺ T cells (<b>A</b>) and PD–1 expression level on tetramer-specific CD8⁺ T cells (<b>B</b>) in the spleen and lungs of wild-type and CIITA^Tg mice are represented. Percentages of CD127⁺ cells among virus-specific CD8⁺ T cells in the indicated tissues are also summarized in the bar graph (<b>C</b>). (<b>D and E</b>) Splenocytes were restimulated <i>in vitro</i> with GP33, GP276, or LCMV peptide pool (GP33, GP276, GP_118-125, GP_92-101, and GP_70-77) and stained for CD8⁺ T cells. Frequency of IFN-γ- and TNF-α-producing CD8⁺ T cells were analyzed by flow cytometry (<b>D</b>), and absolute numbers of CD8⁺ T cells producing IFN-γ and producing both IFN-γ and TNF-α in the spleen are summarized, respectively (<b>E</b>). Numbers in the plots indicate the percentage of TNF-α⁺ and TNF-α^- CD8⁺ T cells producing IFN-γ, respectively. (<b>F</b>) Viral titers were checked in the spleen and kidney extracted from LCMV CL-13-infected mice at 31 DPI. Dashed line indicates the virus detection limit. Undetectable samples were given a half of detection limit. Bar graphs show mean + SD. Data are representative of three independent experiments (n≥3 per group in each experiment). NS, not significant; *<i>P</i><0.05; **<i>P</i><0.01; ***<i>P</i><0.001.