Figure 3. Selective requirement for type I IFN sensing in the DCs.

A. Bone-marrow chimeric mice (WT→IFNAR^−/−, WT→WT, IFNAR^−/−→WT, IFNAR^−/−→IFNAR^−/−) were immunized i.p. with irradiated 5E1-TAKO cells and the frequency of E1B_192-200-specific CD8⁺ T cells in the spleens was determined 7 days later (white bar, control peptide; black bar, E1B_192-200 peptide). B. The effect on memory formation using these chimeras was determined by measuring antigen-specific T cell expansion ex vivo. Secondary expansion of E1B_192-200-specific CD8⁺ T cells was calculated by dividing the absolute number of E1B_192-200-specific CD8⁺ T cells at the end of a6 day culture by the absolute number at the start of the culture. C. WT/CD90.1 mice were irradiated and reconstituted with WT, IFNAR^−/− or a 1:1 ratio of WT (CD45.1):IFNAR^−/−(CD45.2) bone-marrow. Mice were i.p. immunized with irradiated 5E1-TAKO cells and the frequency of splenic E1B_192-200-specific CD8⁺ T cells in each graft was determined 7 days later. D. WT^CD11cDTR:IFNAR^−/− and WT:IFNAR^{−/−CD11cDTR} mixed bone-marrow chimeras were treated with DT or vehicle and immunized with irradiated 5E1-TAKO cells. The frequency of E1B_192-200-specific CD8⁺ T cells in the WT compartment was determined 7 days later. E. Freshly isolated WT and IFNAR^−/− DCs were incubated with irradiated 5E1-TAKO cells, sorted and i.v. injected into WT and IFNAR^−/− mice. The frequency of splenic E1B_192-200-specific CD8⁺ T cells was determined 7 days later. Data of representative experiments (out of 3–5) are shown (mean± s.e.m, n=5/group).