Type I IFN production and viral replication in MHV-infected in vitro–derived cDCs and pDCs. Infection of bone marrow–derived pDCs and cDCs with MHV. (A,C) IFN-α and virus titers in tissue culture supernatants were determined at the indicated times after MHV infection (moi = 1), or (B,D) at 24 hours after MHV infection with different moi as indicated. Values in panels A-D represent means ± SD from triplicate measurements. Experiments in panels A-D were repeated 3 times with comparable results. Expression of IFN-β, IP-10, IFN-α4, IFN-α, GAPDH, or MHV nucleoprotein (MHV-N) mRNAs was determined by RT-PCR using total RNA from bone marrow–derived (E) cDCs or (F) pDCs infected with MHV (moi = 1) or treated with PBS (mock). (G-H) Viral replication in MHV-infected wt or IFNAR^−/− pDCs. Cells were infected with MHV A59 at (G) an moi of 1 or (H) at different moi as indicated. Virus titers in culture supernatants were determined by plaque assay at (G) the indicated times after MHV A59 infection (moi = 1) or (H) 24 hours after MHV infection. (A-D,G-H) Data represent mean values ± SD pooled from 2 experiments. Statistical analysis was performed using Student t test (*P < .05; **P < .01, ***P < .001).