Equine arteritis virus does not induce interferon production in equine endothelial cells: identification of nonstructural protein 1 as a main interferon antagonist.

Yun Young Go,Udeni B R Balasuriya,Yanhua Li,Dongwan Yoo,Mingyuan Han,Ying Fang,Zhenhai Chen

doi:10.1155/2014/420658

Abstract

The objective of this study was to investigate the effect of equine arteritis virus (EAV) on type I interferon (IFN) production. Equine endothelial cells (EECs) were infected with the virulent Bucyrus strain (VBS) of EAV and expression of IFN-β was measured at mRNA and protein levels by quantitative real-time RT-PCR and IFN bioassay using vesicular stomatitis virus expressing the green fluorescence protein (VSV-GFP), respectively. Quantitative RT-PCR results showed that IFN-β mRNA levels in EECs infected with EAV VBS were not increased compared to those in mock-infected cells. Consistent with quantitative RT-PCR, Sendai virus- (SeV-) induced type I IFN production was inhibited by EAV infection. Using an IFN-β promoter-luciferase reporter assay, we subsequently demonstrated that EAV nsps 1, 2, and 11 had the capability to inhibit type I IFN activation. Of these three nsps, nsp1 exhibited the strongest inhibitory effect. Taken together, these data demonstrate that EAV has the ability to suppress the type I IFN production in EECs and nsp1 may play a critical role to subvert the equine innate immune response.

Highlights

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a respiratory and reproductive disease of horses [1, 2]
Sendai virus- (SeV-)induced IFN-β mRNA expression, at both 3 and 6 hpi, was significantly suppressed in cells previously infected with EAV
vesicular stomatitis virus (VSV)-GFP replication was not inhibited in MDBK cells that were preincubated with cell culture supernatant from endothelial cells (EECs) infected with EAV alone

Summary

Introduction

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a respiratory and reproductive disease of horses [1, 2]. EAV is a small enveloped virus with a positive-sense, single-stranded RNA genome of ∼12.7 kb. It belongs to the family Arteriviridae (genus Arterivirus, order Nidovirales), which includes porcine reproductive and respiratory syndrome virus (PRRSV), simian hemorrhagic fever virus (SHFV), and lactate dehydrogenase-elevating virus (LDV) of mice [3,4,5]. The remaining eight ORFs (2a, 2b, and 3, 4, 5a, 5b, and 6-7) are located in the 3󸀠 quarter of the genome and encode the structural proteins (E, GP2, GP3, GP4, ORF5a protein, GP5, M, and N, resp.) of the virus [5, 6, 11,12,13]

Objectives

Methods

Results

Conclusion