Innate immune response mediated by interferon during influenza B virus infection / 中国生物制品学杂志

@#ObjectiveTo explore the innate immune response mediated by interferon(IFN) induced by influenza B virus(IBV)infection.MethodsThe activation of IFN signaling pathway and the expression of IFN-stimulated genes were detected by qPCR using Madin Darby canine kidney(MDCK)cells infected with IBV as model. The supernatants of MDCK cells infected with IBV for 36 h and 48 h were collected and mixed with fresh medium to culture MDCK cells infected with IBV. The antiviral effect of endogenous IFN was detected by qPCR. After adding JAK-STAT pathway inhibitor CP,the supernatant of IBV infected MDCK cells was collected and the cells were cultured. The effect of JAK-STAT pathway inhibition on the antiviral effect of endogenous IFN was detected by qPCR.ResultsIBV effectively activated IFN signal pathway and induced the production of cytokines dominated by typeⅠIFN(IFNα,IFNβ)and typeⅢIFN(IFNλ1,IFNλ3).Meanwhile,MDCK cells infected with IBV induced a series of IFN-stimulated genes(ISGs)with broad-spectrum antiviral effect,such as ISG15,CCL5,CXCL10,MX1 and RIG-I. After CP was used to inhibit JAK-STAT pathway,the ability of ISGs production induced by IBV infection in MDCK cells and the corresponding antiviral effect were significantly inhibited.ConclusionMDCK cells infected with IBV effectively activated type Ⅰ and type Ⅲ IFN mediated JAK-STAT signaling pathways,which provided a reference for the further understanding the interaction between IBV and host.

Topological analysis of IFN-induced transmembrane proteins in porcine peripheral blood lymphocytes and changes of transcription level after infection with porcine reproductive and respiratory syndrome virus / 中国生物制品学杂志

@#Objective To analyze the topology of IFN-induced transmembrane(IFITM) protein in porcine peripheral blood lymphocytes(PBMCs) and detect the change of IFITM mRNA transcription in PBMCs after porcine reproductive and respiratory syndrome virus(PRRSV) infection in vitro.Methods PRRSV,porcine circovirus 2(PCV2) and Japanese encephalitis virus(JEV) negative anticoagulant blood of piglets were collected aseptically and isolated for PBMCs.Porcine IFITM CDS sequence was amplified by PCR,sequenced and analyzed for topology.PBMCs were infected with PRRSV in vitro.Cell samples were collected at 12,24,36 and 48 h after infection,detected for PRRSV infection by RT-PCR,and detected for mRNA transcription level changes of IFITM1,IFITM2 and IFITM3 by RT-PCR.Results The porcine PBMCs were successfully isolated and the full-length sequence of IFITM CDS derived from PBMCs was cloned.The porcine IFITM protein might have two topological structures.PBMCs inoculated with PRRSV for 24 h produced obvious cytopathic effect.PRRSV was replicated in PBMCs.The transcription levels of IFITM1,IFITM2 and IFITM3 mRNA in PBMCs were significantly up-regulated at the early stage of PRRSV infection,and reached the peak at 12h after infection,and then gradually decreased;The transcription level of IFITM1 mRNA increased at 36 h after virus infection and then declined rapidly.Conclusion PRRSV infection in vitro significantly up-regulated the transcription level of IFITM mRNA in PBMCs,indicating that IFITM was involved in the antiviral immune response of PBMCs.This study provided a reference for revealing the natural immune response against PRRSV in vivo.