Reduced lung viral titers of challenged IFN-α/βR^−/− mice that received passive transfer of serum eluate and purified IgG from MuV-IA-immunized mice.

BALB/c mice were immunized i.n. with 1x10⁶ PFU of MuV-IA in a volume of 100 μL. Mice were boosted at 3 and 5 wpi, and serum was collected and pooled at 8 wpi. IgG was purified by affinity chromatography as described in materials and methods and dialyzed in PBS. Column eluate (referred to as serum eluate) was collected during IgG purification. Naïve IFN-α/βR^−/− mice received passive transfer i.p. of 1 mL PBS, serum eluate, or purified IgG. Mice were challenged 24 hours post passive transfer i.n. with 1x10⁶ PFU of MuV-IA in a volume of 100 μL. Lungs were collected and homogenized 2 dpi and viral titers were determined by plaque assay in duplicate. The limit of detection of 5.4 PFU/g tissue is represented by the dashed line. ANOVA and Tukey multiple comparison tests were used to calculate P values.