The Effects Of BHV-1 Infection On Expression Of TLR2 And TLR9 Of Bovine Embryo Tracheal Cells

BHV-1 is the pathogen of infectious bovine rhinotracheitis (IBR), and it mainly against respiratory system,reproductive system,nervous system,ocular conjunctiva and fetus. BHV-1 not only evade the immune system but also undergoe latent infection and cause persistent infection.They are the main obstacles to control IBR.TLR is a transmembrane signal transduction protein which has been paid much attention in recent years. It is able to activate the innate immune system and initiate the acquired immune system. TLR2 and TLR9 can mediate innate immune response of herpesvirus infected host. In this paper, EBTr cells were used as non immune cell model of body tissue, Investigating the effect of BHV-1 infection on the expression of TLR2 and TLR9 from gene and protein level, and obtained the following results.(1)The RT-PCR results showed that EBTr cells expressed TLR1,2,3,4,6,7,9,10, Whereas the mRNA of TLR5 and TLR8 were not detected.(2)Establishing the TaqMan fluorescence quantitative PCR method to detected the proliferation of virus in EBTr cells after 6,12,24,48,72,120,96 and 144h BHV-1 infection.It can produce obvious cytopathic effect in EBTr cells after BHV-1 infection,Virus had been proliferated slowly when the cells infected within 144 hours. Furthermore, the changes of cell morphology and the trend of the growth curve of the virus were coincidental.(3)Dividing the EBTr cells into BHV-1 group and control group,culturing 6,12,24 and 48h.Using the Optimized SYBR Green fluorescence quantitative PCR method to detect the changes of expression of TLR2 and TLR9mRNA.The change of TLR2 protein expression was detected by Western blot technique.The experimental reference were β-actin.The results showed that,the relative expression levels of TLR2mRNA and proteins in the BHV-1 group were higher than those in the control group within 48h BHV-1 infection in EBTr cells,and the difference was significant at 48h infection (P<0.01).BHV-1 infection can significantly increase the expression of TLR2mRNA and protein.The relative expression of TLR9mRNA in BHV-1 group was lower than that in control group within 48h infected in EBTr cells, the difference in 24h and 48h were significant (P<0.01).The expression of TLR9mRNA was down regulated by BHV-1 infection.These results indicated that it can lead to changed the expression of TLR2 and TLR9 after BHV-1 infected EBTr cells. It laid a foundation for further study of TLR2 and TLR9 mediated immune mechanism of BHV-1 in EBTr cells.