Reduced cytopathic effect following rChIFN-α pretreatment following AIV infection. Primary chicken lung cell monolayers were pretreated with 1000 U/ml of rChIFN-α and infected with either H1N1 of H5N9 at 0.1 MOI. Negative control cells include no treatment/no virus (A), and IFN-α only (B). Protection from cytopathic effect was observed in cells infected with virus only, H1N1 (C) and H5N9 (E), compared with IFN-α treated cells that were then infected with H1N1 (D) or H5N9 (F). At 24 hpi the monolayers were digitally photographed using an inverted microscope at 200× magnification (Olympus America Inc., Melville, NY).