Recombinant ChIFN-α reduces avian influenza virus replication. Inhibition of avian influenza virus (H1N1 and H5N9) replication in primary lung cell cultures derived from chicken (A), duck (B), and turkey (C) after rChIFN-α (1000 U/ml) pretreatment in vitro. Cells were infected with A/turkey/Virginia/2009 H1N1 or A/turkey/Wisconsin/68 H5N9 at MOI 0.1. Supernatants were harvested at the times indicated and viral titers were determined following injection into SPF embryos. The mean (and standard deviations) of three independent experiments are shown. Different lowercase letters denote significance in titer following rChIFN-α treatment groups (within columns) (P < 0.05) as determined by one-way ANOVA. Statistical differences (P < 0.05) following treatment between virus groups are shown by lowercase letter.