Enhanced proliferation of OVA-specific CD8⁺ T cells in SRA/CD204 KO mice. (A) Enhanced expansion of adoptively transferred OT-I cells in SRA^−/− mice. Mice received CFSE-labeled OT-I cells on day −1, and were immunized with OVA-MPL on day 0. Spleens were harvested at different time points and subjected to FACS analysis by gating on CD8⁺ cells. OT-I cells were also transferred to mice without immunization and used as controls. Data are representative of 2 separate experiments in which at least 3 mice in each group were analyzed. (B) Increased frequency of endogenous OVA-specific CD8⁺ T cells in SRA^−/− mice. Representative FACS dot plots of tetramer staining. WT and SRA^−/− mice (n = 3) were immunized with OVA-MPL. PBLs were collected on day 5 and stained with anti-CD8 antibodies and OVA tetramer. (C) Kinetic analysis of the frequency of OVA-specific CD8⁺ T cells. After immunization, CD8⁺OVA tetramer⁺ T cells in PBLs were assessed on days 3, 5, 7, and 14. Percentage of tetramer-positive cells gated on CD8⁺ T cells. Data shown as mean plus or minus SD are representative of 2 experiments (P < .001, SRA^−/− vs WT mice, ANOVA test). (D) Stronger recall response against OVA in SRA^−/− mice. Two months after vaccination, mice were immunized with OVA, and analyzed for CD8⁺OVA tetramer⁺ T cells in PBLs.