Effect Of REV Infection On TLR3 And Its Related Factors In Immune Organs Of SPF Chickens

Taking 1 day old SPF chicks as the research object,60 chickens were randomly divided into REV infected group(I group)and uninfected virus control group(C group).In order to explore the dynamic changes of the expression of TLR3 and its related factors IRF3,NF-κBp65,IFN-β and their protein content and viral titer in the immune organs of SPF chicks infected with REV,the methods of WB,RT-qPCR and indirect ELISA and etc were used.Systemic study on innate antiviral immunity mediated by TLR3 in thymus,spleen and bursa of Fabricius of SPF chickens infected with REV.The results are as follows:(1)REV was detected in thymus tissue 1 to 28 days after SPF chickens infected with REV;virus was detected in spleen tissue 1 to 3 days after chickens infected;detected in bursal tissue 1 to 14 days after virus infection.No virus was found at the other time.It shows that the length of time the different in different organs of virus exist after SPF chickens infected with REV.(2)TLR3 mRNA expression and protein content in the thymus and bursa of Fabricius were significantly or extremely significantly(P<0.05 or P<0.01)higher than those of control chicks from 1 to 7 days after SPF chickens infected with REV;mRNA expression and protein the content of IRF3 was significantly higher(P<0.05 or P<0.01)than that of the control chicks at 1 to 3 days after virus infected,but significantly or extremely significantly at 21 to 28 days(P<0.05 or P<0.01)lower than the control chicks;IFN-β mRNA expression and protein content were significantly(P<0.05 or P<0.01)higher than the control chicks at 1 to 7 days after REV infected among them,the IFN-β protein content was lower than the control chicks at different levels(P<0.05 or P<0.01)from 21 to 28 days after virus infection.It indicates that early infection of REV can regulate the gene and protein expression of innate immune TLR3 and its related factors in thymus and bursa of Fabricius.(3)The expression of TLR3 mRNA and protein content in the spleen were significantly(P<0.05)or extremely significant(P<0.01)higher than that of the control chickens 1 to 7 days after SPF chickens infected with REV.The expression level of NF-κBp65 mRNA was significantly higher than that of control chicks 3 to 14 days after virus infection(P<0.05 or P<0.01).The expression and protein content of IRF3 and IFN-β mRNA were significantly higher(P<0.05 or P<0.01)than those of the control chicks at 3 to 7 days after virus infection.It was shown that the innate immune TLR3 and its related downstream pathway related factors in the spleen were later than the thymus.(4)The organ indexes of different degree in thymus,spleen,and bursa of Fabricius were all lower than the control chicks at 21 to 28 days after REV infection(P<0.05 or P<0.01).It shows that the reduction of immune organ index caused by REV infection is closely related to the decline immune function of immune organ.In the early stage of REV infection,IFN-β can be induced by activating the expression of TLR3 and related factors in thymus,spleen and bursa of Fabricius and participate in virus clearance.