Figure 6.

Endogenous type I IFN signaling is required for intratumoral accumulation of CD8α⁺ DCs. (A and B) Wild-type and Stat1^−/− mice were inoculated s.c. with 10⁶ B16.SIY cells, and 15 d later tumors were harvested and frequency (A) and percentages (B) of CD8α⁺ DCs, mDCs, and pDCs infiltrating tumors were analyzed by FACS. GFP⁺DAPI⁺CD3⁺ cells were gated out, and the different DCs subpopulations were identified as follows: mDCs, CD11C⁺B220⁻CD8α⁻CD11b⁺; CD8α⁺DCs, CD11C⁺B220⁻CD8α⁺CD11b⁻; and pDCs, CD11C^intB220⁺PDCA⁺. Results are shown as mean ± SEM of 3 independent experiments (n = 4). (C–E) Wild-type and IFN-α/βR^−/− mice were inoculated s.c. with 10⁶ B16.SIY cells, and 15 d later tumors were harvested and frequency of intratumoral CD8α⁺ DCs was assessed by FACS (C). (D and E) XCR1 mRNA expression (D) and Batf3 mRNA expression (E) were assessed by real-time RT-PCR analysis on tumor homogenates. The results are expressed as 2^−ΔCt using 18s as endogenous control. Results are shown as mean ± SEM of 2 independent experiments (n = 5).