Enhancement of CD8+ T cell response by FGK4.5 treatment during VSV infection is dependent on CD70.

C57BL/6 mice were left uninfected, or i.v. infected with 2×103 cfu LM-ova, or with 2×105 pfu VSV-ova alone, or 2×105 pfu plus 100 µg FGK4.5 treated i.p. one day after infection, or 2×105 pfu VSV-ova plus 100 µg FGK4.5 one day post infection and 300 µg FR70, a blocking CD70 mAb, on days −1, +1, and +3 relative to infection. The magnitude of the Ova/Kb-specific memory CD8+ T cell population in the (A) peripheral blood and in the (B) spleen was quantified 60 days post infection. (C) To assess protective immunity, memory mice were re-challenged with 5×105 cfu LM-ova. Three days later bacterial burden was assessed in the spleen and liver. Each experiment contained 4–5 mice per group and data are representative of at least two independent experiments. Statistical significance was determined using a one-way ANOVA with a Bonferroni’s post-test (***p