Analysis of the differential expression and antiviral activity of porcine interferon-α in vitro

Abstract

Abstract Porcine interferon α (poIFN-α) is a crucial cytokine that can prevent and treat viral infection. Seventeen functional porcine IFN-α subtypes were found in the porcine genome. In this study, multiple sequence alignment was performed to analyze IFN-α protein structure and function. Phylogenetic tree analysis of the porcine IFN gene family defined the evolutionary relationship of the various subtypes. Porcine IFN-αs, including porcine IFN-α1–17, were expressed in an E. coli expression system. The antiviral activities of these IFN-α proteins against vesicular stomatitis virus (VSV) and pseudorabies virus (PRV) were examined in PK-15 cells. We found that the antiviral activity of different porcine IFN-α molecules greatly differed: the porcine IFN-α14 and 17 subtypes had the greatest antiviral activities against VSV and PRV in PK-15 cells, porcine IFN-α1, 2, 3, and 8 exhibited lower biological activities, and porcine IFN-α4, 5, 6,7, 9, 10, 11, 12, 13, and 16 had minimal or no effect in the tested target cell‒virus systems. Moreover, our studies demonstrated that the antiviral activity of IFN-α was positively correlated with the induction of IFN-stimulated genes, such as 2’-5’ oligoadenylate synthetase 1 (OSA1), interferon-stimulated gene 15 (ISG15), myxoma resistance protein 1 (Mx1), and Protein kinase R (PKR). Thus, our experimental results provide important information for understanding the antiviral functions and mechanism of porcine IFN-α.