VV specific Th17 cells are relatively enriched in the CNS compartment of α4 CKO mice but do not control i.th. VV infection. CD4 Cre
flox/flox mice (controls, WT) and α4 CKO mice were immunized with MVA/CFA, depleted of CD8+ T cells, and challenged i.th. with VV. (A) After intrathecal infection with VV, the clinical course was monitored and weight loss was calculated as percentage of initial body weight (n = 5 per group). On day 5 after infection, mice of each group were sacrificed. (B) The efficacy of CD8+ T cell depletion was analyzed by flow cytometry in CNS mononuclear cells (gate on CD3+CD19- cells). (C) The viral load in the CNS was measured by means of plaque assay. CNS infiltrating CD4+ T cells (D) and absolute numbers of cytokine positive CD4+ T cells (E) were calculated by surface staining and intracellular cytokine analysis (Student’s t test, n ≥ 4 per group, representative out of n ≥ 4 independent experiments). (F) CD4+ T cells were isolated by flow cytometric purification from the CNS compartment of MVA immunized wild type vs α4 CKO mice 5 days after i.th. VV challenge. The expression profile of the indicated genes was determined by quantitative PCR analysis, n = 4.