Gene Expression and Antiviral Activity of Interleukin-35 in Response to Influenza A Virus Infection

Li Wang,Shengli Zhu,Gang Xu,Jian Feng,Tao Han,Fanpeng Zhao,Ying-Long She,Shi Liu,Linbai Ye,Ying Zhu

doi:10.1074/jbc.m115.693101

Abstract

Interleukin-35 (IL-35) is a newly described member of the IL-12 family. It has been reported to inhibit inflammation and autoimmune inflammatory disease and can increase apoptotic sensitivity. Little is known about the role of IL-35 during viral infection. Herein, high levels of IL-35 were found in peripheral blood mononuclear cells and throat swabs from patients with seasonal influenza A virus (IAV) relative to healthy individuals. IAV infection of human lung epithelial and primary cells increased levels of IL-35 mRNA and protein. Further studies demonstrated that IAV-induced IL-35 transcription is regulated by NF-κB. IL-35 expression was significantly suppressed by selective inhibitors of cyclooxygenase-2 (COX-2) and inducible nitric-oxide synthase, indicating their involvement in IL-35 expression. Interestingly, IL-35 production may have suppressed IAV RNA replication and viral protein synthesis via induction of type I and III interferons (IFN), leading to activation of downstream IFN effectors, including double-stranded RNA-dependent protein kinase, 2',5'-oligoadenylate synthetase, and myxovirus resistance protein. IL-35 exhibited extensive antiviral activity against the hepatitis B virus, enterovirus 71, and vesicular stomatitis virus. Our results demonstrate that IL-35 is a novel IAV-inducible cytokine, and its production elicits antiviral activity.

Highlights

Seasonal influenza A virus (IAV)2 is a common human infection, resulting in significant morbidity and mortality [1]
These results are similar to those obtained from throat swabs; EBI3 mRNA levels were ϳ6-fold higher (IAV, 56.09 Ϯ 10.23, n ϭ 10, black box; controls,10.44 Ϯ 3.803, n ϭ 10, white box; **, p Ͻ 0.01, Fig. 1B, left), and p35 mRNA levels were ϳ4-fold higher (IAV, 98.30 Ϯ 21.82, n ϭ 10, black box; controls, 26.57 Ϯ 7.483, n ϭ 10, white box; **, p Ͻ 0.01, Fig. 1B, right) in IAV-infected patients compared with controls
A statistically significant correlation was observed between NP and IL-35 mRNA levels in peripheral blood mononuclear cells (PBMCs) from IAV-infected patients (NP and IL-35/EBI3: r ϭ 0.70, n ϭ 33; **, p Ͻ 0.01, Fig. 1C, left; NP and IL-35/p35: r ϭ 0.73, n ϭ 33; **p Ͻ 0. 01, Fig. 1C, right)

Summary

Introduction

Seasonal influenza A virus (IAV)2 is a common human infection, resulting in significant morbidity and mortality [1]. A statistically significant correlation was observed between NP and IL-35 mRNA levels in PBMCs from IAV-infected patients Similar results were obtained in IAV-infected PBMCs: both IL-35/EBI3 and IL-35/p35 mRNA reached peak expression 24 hpi (data not shown).

Results

Conclusion