Modulation of type 1 interferon by porcine reproductive and respiratory syndrome virus

Thumbnail Image
Lai, Frances W.
Journal Title
Journal ISSN
Volume Title
University of Guelph

Porcine reproductive and respiratory syndrome virus (PRRSV) suppresses the anti-viral immune response of type I interferon (IFN) cytokines. This is a key contributor to the ability of PRRSV to persist in swine. This study examined the suppression of IFN-[alpha] 'in vitro' and the mechanism by which this occurs. By conventional RT-PCR and quantitative real-time RT-PCR, IFN-[alpha] mRNA appeared to be diminished during PRRSV infection of Marc-145 cells. Based on observations in the Marc-145 cell system, examination of IFN transcription factor interferon regulatory factor 3 (IRF-3) by luciferase reporter assay, immunofluorescence, and Western blot indicated that activation of IRF-3 did not appear to occur in cells infected with PRRSV. It was also found that PRRSV N protein had a negative effect on IRF-3 activation in HeLa cells. IRF-3 is an essential transcription factor for type I IFN expression and PRRSV may suppress the innate immune response through deactivation of IRF-3.

porcine reproductive and respiratory syndrome virus, anti-viral immune response, type I interferon cytokines, suppression, IFN-[alpha]