Avian influenza virus H5N1 induces rapid interferon-beta production but shows more potent inhibition to retinoic acid-inducible gene I expression than H1N1 in vitro

• Main Authors: Mi Zhiqiang, Ma Yonghong, Tong Yigang
• Format: Article
• Language: English
• Published: BMC 2012-08-01
• Series: Virology Journal
• Subjects: Avian influenza virus H5N1; Interferon-beta; RIG-I
• Online Access: http://www.virologyj.com/content/9/1/145

<p>Abstract</p> <p>Background</p> <p>The mechanisms through which the avian influenza virus H5N1 modulate the host’s innate immune defense during invasion, remains incompletely understood. RIG-I as a pattern recognition receptor plays an important role in mediating innate immune response induced by influenza virus. So, modulating RIG-I might be adopted as a strategy by influenza virus to antagonize the host’s innate immune defense.</p> <p>Methods</p> <p>Here we chose an avian influenza virus A/tree sparrow/Henan/1/04 (H5N1) directly isolated from a free-living tree sparrow in Mainland China which is amplified in egg allantoic cavity, and researched its interferon induction and manipulation of RIG-I expression compared with influenza virus A/WSN/1933(H1N1), a well characterized mouse adapted strain, in human lung epithelial A549 cells and human embryonic kidney 293T cells.</p> <p>Results</p> <p>Although the avian influenza virus H5N1 infection initiated a rapid IFN-beta production early on, it eventually presented a more potent inhibition to IFN-beta production than H1N1. Correspondingly, the H5N1 infection induced low level expression of endogenous RIG-I, an Interferon Stimulating Gene (ISG), and showed more potent inhibition to the expression of endogenous RIG-I triggered by exogenous interferon than H1N1.</p> <p>Conclusions</p> <p>Manipulating endogenous RIG-I expression might constitute one of the mechanisms through which avian influenza virus H5N1 control the host’s innate immune response during infection.</p>