FIG. 2.

T-cell responses are reduced in MyD88^−/− TRIF^−/− mice. Wild-type B6 and MyD88^−/− TRIF^−/− mice were infected with 5 × 10² PFU of PR8 virus. As a control, wild-type B6 mice were challenged with PBS (naïve). Mononuclear cells from MdLN and spleen were isolated 4 weeks later and cocultured with 10 μg/ml inactivated PR8 virus. (A) Cell proliferation was assessed by [³H]thymidine incorporation. Data are representative of three independent experiments; values are means + standard deviations of triplicate experiments. (B) Th1/Th2 cytokine profiles were determined in culture supernatant of mononuclear cells by a CBA kit. Results are representative of three experiments (n = 3 for each group). (C) Virus-specific CD8 T cells stained with nucleoprotein-specific tetramer from MdLN and spleen of naïve or infected mice (n = 3). **, P < 0.01 versus wild-type control.