Cytokine secretion and activation of CD11c⁺ splenocytes, IPCs, CD11b⁺ DCs, CD11b^– DCs, and bone marrow–derived IPCs from wild-type and TLR9–/– mice in response to HSV-1 in vitro. (A) Wild-type (▪) and TLR9–/– (▨) CD11c⁺ splenocytes were cultured for 36 hours (2 × 10⁶ cells/mL) with HSV-1 at the indicated MOI or 3 μg/mL CpG ODN 2216. (B) IPCs (top row), CD11b⁺ DCs (middle row), and CD11b^– DCs (bottom row) were sorted from wild-type and TLR9–/– CD11c⁺ splenocytes and were cultured with 2 MOI HSV-1 and 1 MOI influenza virus PR8 for 36 hours (2 × 10⁴ cells/150 μL/well). (C) Wild-type and TLR9–/– bone marrow–derived IPCs were incubated with HSV-1 (0.01-10 MOI) or CpG 2216 (3 μg/mL). IFN-α and IL-12 were measured in the supernatants using ELISA. CD86 expression was measured by flow cytometry and is expressed as median fluorescence intensity. Dashed line indicates the median value of the isotype control sample.