The mRNA and Proteins Expression Levels Analysis of TC-1 Cells Immune Response to H9N2 Avian Influenza Virus.

Jiyuan Liu,Tongjie Chai,Liangmeng Wei,Dan Meng,Mengchan Hao,Ning Li

doi:10.3389/fmicb.2016.01039

Abstract

Since 1994, the H9N2 avian influenza virus (AIV) has spread widely in mainland China, causing great economic losses to the poultry industry there. Subsequently, it was found that the H9N2 AIV had the ability to infect mammals, which gave rise to great panic. In order to investigate the immune response of a host infected with H9N2 AIV, TC-1 cells were set as a model in this research. Quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay methods were used to study the expression changes of pattern recognition receptors (PRRs), inflammatory cytokines, and chemokines in AIV-infected TC-1 cells. Our research found that TC-1 cells had similar susceptibility to both CK/SD/w3 (A/Chicken/Shandong/W3/2012) and CK/SD/w4 (A/Chicken/Shandong/W4/2012) H9N2 isolates, while the CK/SD/w3 isolate had a stronger capability of replication in the TC-1 cells. At the same time, the expression of PRRs (melanoma differentiation-associated gene 5, MDA-5), cytokines [interleukin (IL)-1β and IL-6], and chemokines [regulated on activation, normal T cell expressed and secreted (RANTES) and interferon-γ-induced protein-10 kDa (IP-10)] were significantly up-regulated. These results indicated that MDA-5, IL-1β, IL-6, RANTES, and IP-10 might play important roles in the host immune response to H9N2 AIV infection. This study provided useful information for further understanding the interaction between H9N2 virus infection and host immunity, and had certain guiding significance for the prevention and treatment of this disease.

Highlights

H9N2 avian influenza viruses (AIVs), which belong to the Orthomyxoviridae family, have been circulating worldwide in many avian species and have led to great economic losses (Li et al, 2005; Ducatez et al, 2008; Nagarajan et al, 2009)
TC-1 cells were derived from mouse lung epithelial, which we purchased from the China Center for Type Culture Collection, where they were grown as monolayers in RPMI-1640 medium (Gibco) supplemented with 10% fetal bovine serum (FBS), 100 U/ml penicillin, and 100 μg/ml streptomycin at 37◦C in a 5% CO2 incubator
We focused on Toll-like receptors (TLRs)-3 and TLR-7, which are involved in responses to RNA viruses, as well as MDA5, which responds to double-stranded RNA

Summary

Introduction

H9N2 avian influenza viruses (AIVs), which belong to the Orthomyxoviridae family, have been circulating worldwide in many avian species and have led to great economic losses (Li et al, 2005; Ducatez et al, 2008; Nagarajan et al, 2009). What’s more, human cases of H9N2 AIV infection have been reported in Hong Kong and mainland China since. Specific antibodies to H9N2 AIV were detected in poultry workers and patients (Guo et al, 1999; Guan et al, 2000; Lin et al, 2000). These findings pointed to a possibility that H9N2 AIV could infect humans directly, which caused great public concern. More and more researchers have paid attention to H9N2 AIV in recent years (Maines et al, 2008)

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Conclusion