Characterization and virus-induced expression profiles of the porcine interferon-omega multigene family.

Interferon-omega is a member of the type I interferon family. In this work, 8 functional porcine interferon-omega genes and 4 pseudogenes present on porcine chromosome 1 were identified in the porcine genome database by BLAST scanning. Their genetic and genomic characteristics were investigated using bioinformatics tools. Then the PoIFN-omega functional subtype genes were isolated and expressed in BHK-21 cells. The PoIFN-omega subtypes possessed about 10(4) to 10(5) units of antiviral activity per milliliter. PoIFN-omega 7 had the highest antiviral activity, about 20 times that of PoIFN-omega 4, which had the lowest antiviral activity. Differential expression of the subtypes was detected in PK15 cells and porcine peripheral blood mononuclear cells (PBMCs) in response to pseudorabies virus and poly(I).poly(C). Expression of PoIFN-omega 2/-omega 6 was up-regulated to the greatest extent by virus infection.