Impaired anti-viral CD4 and CD8 T cell responses in OX40−/− mice.

WT (black circles) and OX40−/− (white circles) mice were intravenously infected with 2×106 PFU of LCMV cl13. (A) Loss of body weight was measured twice weekly as a marker for disease severity. (B, C) Virus-specific splenic T cell populations in WT and OX40−/− mice were analyzed 20 days post infection using GP33-pentamers (B, CD8) and GP66-tetramers (C, CD4). (D–H) Splenocytes of infected mice were harvested 10, 20 and 50 days post infection. Intracellular cytokine stainings (ICCS) were performed following in vitro stimulation with immunodominant CD8 (D–F) and CD4 (G, H) epitopes as illustrated. (I) Representative ICCS staining following GP61 stimulation, gated on CD4 T cells. Data are derived from a total of 7 independent experiments, 1–2 experiments per time point.