The protective role of TLR3 and TLR9 ligands in human pharyngeal epithelial cells infected with influenza A virus

Abstract

In this study we aim to extensively investigate the anti-influenza virus immune responses in human pharyngeal epithelial cell line (Hep-2) and evaluate the protective role of T oll-like receptor (T LR) ligands in seasonal influenza A H1N1 (sH1N1) infections in vitro. We first investigated the expression of the T LRs and cytokines genes in resting and sH1N1 infected Hep-2 cells. Clear expressions of T LR3, T LR9, interleukin (IL)-6, tumour necrosis factor (T NF)-α and interferon (IFN)-β were detected in resting Hep-2 cells. After sH1N1 infection, a ten-fold of T LR3 and T LR9 were elicited. Concomitant with the T LRs activation, transcriptional expression of IL-6, T NF-α and IFN-β were significantly induced in sH1N1-infected cells. Pre-treatment of cells with poly I:C (an analog of viral double-stranded RNA) and CpG-ODN (a CpG-motif containing oligodeoxydinucleotide) resulted in a strong reduction of viral and cytokines mRNA expression. The results presented indicated the innate immune response activation in Hep-2 cells and affirm the antiviral role of Poly I:C and CpG-ODN in the protection against seasonal influenza A viruses. Copyright © 2014 The Korean Physiological Society and The Korean Society of Pharmacology.