T cell responses in the CNS and the periphery of TMEV-infected B6 and IL-1R knockout (KO) mice. (A) Levels of Th1 and Th17 cells in the central nervous system (CNS) of virus-infected B6 and IL-1R KO mice were assessed using flow cytometry at 8 days post-infection (dpi) after stimulation with PBS, PMA/ionomycin, anti-CD3/CD28 antibodies, or viral epitope peptides (Pep: mixture of 2 μM VP2203-220 and 2 μM VP425-38). The flow cytometric plots show gated CD4+ T cells. (B) The numbers of CNS-infiltrating IFN-γ-producing CD4+ T cells reactive to either viral epitope peptides (CD4: equal mixture of VP2203-220 and VP425-38) or anti-CD3/CD28 antibodies in virus-infected B6 and IL-1R KO mice (three mice each) at 8 and 21 dpi. A representative result from two to three similar experiments is shown here. (C) Levels of proliferation and cytokine production by splenic T cells in response to viral epitopes by CD4+ T cells (CD4 Mix: equal mixture of VP2203-220 and VP425-38), CD8+ T cells (VP2-121–130), or both CD4+ and CD8+ T cells (anti-CD3/CD28 antibodies) were assessed at 8 and 21 dpi. Values are expressed as the mean of triplicate samples (mean ± SD) from a representative of three experiments. *P < 0.05, **P < 0.01, ***P < 0.001.