FIGURE 6.

Signaling through the type I IFN receptor is important for the maturation of host alloantigen-presenting DCs and the priming of alloreactive CD8⁺ T cells. A and B, C57BL/6 and C57BL/6.IFNARI^−/− mice were injected with 10 × 10⁶ CFSE-labeled BALB/c DST and 0.5 mg of anti-CD154 mAb without or with an i.p. injection of LPS. Fifteen hours later, splenocytes were harvested, stained with Abs to H2-K^b (host), CD8α, CD11c, and CD86 and analyzed by flow cytometry. Data are representative of two independent experiments with at least three mice per group. A, MFI of the MHC class I molecule H2-K^b. *, p < 0.01 vs all other groups. #, p = NS vs wild-type mice treated with DST and anti-CD154 mAb; p < 0.01 vs wild-type mice treated with DST, anti-CD154 mAb, and LPS; p < 0.05 vs IFNAR1^−/− mice treated with DST and anti-CD154 mAb. B, MFI of CD86. *, p < 0.05 vs IFNAR1^−/− mice treated with DST, anti-CD154 mAb, and LPS; p < 0.001 vs both IFNAR1^−/− and wild-type mice treated with DST and anti-CD154 mAb. #, p < 0.01 vs both IFNAR1^−/− and wild-type mice treated with DST and anti-CD154 mAb. C, All mice were treated with a BALB/c DST, bone marrow, and anti-CD154 mAb according to our standard protocol without or with an i.p. injection of 100 µg of LPS. Splenocytes were harvested 1 wk after bone marrow transplantation, stimulated in vitro with either irradiated syngeneic (H2^b) or allogeneic (H2^d) splenocytes, and analyzed by flow cytometry for intracellular IFN-γ production. The percentage of CD8⁺ lymphocytes producing IFN-γ is shown (bar represents the mean). Data are pooled from two independent experiments. #, p < 0.05 vs wild-type C57BL/6 mice treated with DST, anti-CD154 mAb, and LPS. p = NS vs IFNARI^−/− treated with DST and anti-CD154 mAb.