FIG. 3.

IFN-α/β expression in vivo involves at least three mechanisms with differential requirements for TLR9 and virus replication. C57BL/6 or TLR9^−/− mice were infected i.p. with 2 × 10⁷ PFU of infectious or inactivated HSV-1 (A and C) or HSV-2 (B and D) (five mice per group). After 8 h (A and B) or 16 h (C and D) of treatment, serum was harvested, and the levels of IFN-α/β were measured by bioassay. (E and F) Splenic cDCs and macrophages were harvested from TLR9^−/− mice infected as described above for 16 h. The cells were cultured for 24 h, and the ex vivo production of IFN was measured by bioassay. Similar results were obtained in three independent experiments. Error bars indicate the SEM. *, P < 0.05.