Comparison of the antiviral activities of ChIFN-α and ChIFN-β on DF-1 cells by the CPE inhibition assay.

<p>(A) Anti-VSV activities of ChIFNs at different time points. Cells were pretreated with serial four-fold dilutions of ChIFN-α or ChIFN-β for different durations (2, 4, 8, 12, or 24 h) before VSV infection and then stained with crystal violet. (B) Antiviral titration curves of the ChIFNs. DF-1 cells were untreated or treated with 10-fold serial dilutions of ChIFN-α or ChIFN-β for 12 h before VSV infection and then stained with crystal violet. The relative survival percentage was calculated as the ratio of OD values between IFN-treated wells and untreated wells. (C) Antiviral activities of ChIFNs against VSV, NDV and AIV. Cells were treated with serial four-fold dilutions of ChIFN-α or ChIFN-β for 12 h, followed by VSV, NDV or AIV infection, and then stained with crystal violet. (D) Anti-VSV activities of ChIFNs on different cell lines. DF-1, MDBK, MDCK, and WISH cells were treated with serial four-fold dilutions of ChIFN-α or ChIFN-β for 12 h, followed by VSV infection, and staining with crystal violet. The antiviral activities of ChIFN-α and ChIFN-β were represented as the reciprocal of dilutions that led to 50% virus-induced cells lysis. Data were shown as mean ± SD (n = 3). ND: the activity was undetectable.