Effect of antibody-mediated pDC depletion on MHV infection. 129Sv mice were treated with rat IgG2b (wt isotype control) or α–mPDCA-1 (wt PDCA-1) and infected intraperitoneally with 5 pfu MHV A59 (n = 6). IFNAR^−/− mice (n = 3) were used to demonstrate uncontrolled MHV spread in the absence of a functional IFN system. (A) IFN-α concentration in serum (means ± SD), (B) viral titers (means ± SD) in liver, spleen, brain, and lung, and (C) serum ALT values (means ± SD) were assessed at 48 hours after infection. (A-C) Statistical analysis was performed using Student t test (*P < .05; **P < .01).