FIG 4.

Impact of type I IFNs on CD8⁺ T cell memory formation. SV129 (WT) and IFN-AR1^−/− mice were immunized with 10⁶ IU of VREP-OVA and given a homologous boost 9 weeks later. Each immunized group consisted of eight mice, and naive groups consisted of four mice. (A) Mice were sacrificed, spleens were collected, and SIINFEKL-specific CD8⁺ T cells were assessed by IFN-γ ELISPOT at 5 days or 5 weeks postboost. Lines represent medians. **, P < 0.01; ***, P < 0.001. (B) At 5 weeks postboost, pentamer⁺ CD8⁺ T cells and proportions of these cells that expressed CD62L/CD127 or CD27/CD43 were also assessed by flow cytometry analysis.