Figure 6.

Combined CD8⁺ and CD4⁺ T cell depletion reverses the protective effect of the CHKVf5 vaccine. (A) Mice vaccinated with MCMV-CHKVf5 and boosted with AdV-CHKVf5, or control vectors were treated with 300 μg rat isotype control, anti-CD4, anti-CD8, or anti-CD4 plus anti-CD8 depleting antibodies at 2 days prior to challenge. Mice were infected i.m. with 10,000 PFU CHIKV SL15649, and (B) ankle and calf tissue viral loads were measured by limiting dilution plaque assays. Statistical analysis was performed on log-transformed data using Dunn's multiple comparison test (**p < 0.005; ****p < 0.0001; n = 9). (C) Neutralization assays were performed using mouse serum isolated at 5 dpi. (D) Splenocytes from vaccinated mice were collected and stimulated with CHIKV peptides on ELISpot plates. The results of the ELISpot assay are reported (n = 4).