Immunomodulatory Effect Of CXCR5+CD8+T Cells In Chronic Hepatitis B Virus Infection

BackgroundAccording to the world health organization reported,about 2 billion people had hepatitis B virus(HBV)infection,and 240 million people were estimated to be chronically infected worldwide.Each year about 650000 people died of liver failure,liver cirrhosis and hepatocellular carcinoma(HCC),and other complications after HBV infection.A survey about 1～29 years old population of hepatitis B serum epidemiology showed 1～4,5～14 and 15～29 years old people of hepatitis B virus surface antigen(HBsAg)detection rate was 0.32%,0.94%and 4.38%,respectively conducted by The Chinese center for disease control and prevention(CDC)in 2014.Chronic hepatitis B viral hepatitis(CHB)is resulted of HBV infect that spread through blood,maternal and infant vertical transmission and sexually transmitted infection caused human liver diseasesThe European society for the study of liver diseases(EASL)and the American society for the study of liver diseases(AASLD)think one of antiviral therapy discontinuation indicator is HBeAg seroconversion in HBeAg positive CHBIn response to infection,antigen-specific CD8+T cells are primed in the T cell zone of secondary lymphoid organs and differentiate into effector cytotoxic T cells(TC cells)to eliminate infected cells.Concurrently,CD4+T cells differentiate into follicular helper T cells(Tfh cells)that localize to B cell follicles and promote protective antibody responses.During chronic viral infection,virus-specific CD8+T cells become exhausted,exhibit poor effector function and lose memory potential.Nevertheless,exhausted CD8+T cells can still contain viral replication in chronic infections,although the mechanism is largely unknown.Here we identified a specialized group of cytotoxic T cells(CTLs)that expressed the chemokine receptor CXCR5,selectively entered B cell follicles and eradicated infected Tfh cells and B cells as follicular cytotoxic T cells(Tfc)during chronic infections.Human immunodeficiency virus(HIV)and epstein-barr virus(EBV)persist in Tfh cells and B cells,respectively.The CXCR5+subset selectively entered B cell follicles and expressed low level of inhibitory receptors play a powerful cytotoxicity than the CXCR5" subset during lymphocytic choroid plexus virus meningitis(LCMV)and HIV chronic viral infection.During chronic viral infection and Cancer patients,T cells become exhausted,However,CXCR5+CD8+T cells in the role of HBV infection has not been reported.The HBV transfection mouse model is established by injecting HBV gene-containing vectors through intravenous hydrodynamic or commonly injecting HBV gene-containing hepatotropic virus vectors.ObjectiveThrough transverse/longitudinal cohort of chronic HBV infection and HBVmice model,to research CXCR5+CD8+T cells characteristics in the process of HBV infection.Methods1.Flow cytometry(FCM)detect CXCR5+CD8+T cells frequency of CHB without treated and chronic hepatitis B patients antiviral treatment.Quantitative polymerase chain reaction(QPCR)quantitative detect intrahepatic CXCL13 expression levels of HBV patients,and enzyme linked immunosorbent assay(ELISA)detect the alanine aminotransferase(ALT)levels.2.Magnetic bead separated peripheral blood CD8+T cells of HBeAg positive early cure CHB patients.FCM detecting CXCR5+CD8+T cells frequency,phenotype and function.3.FCM detecting CXCR5+CD8+T cells frequency,phenotype and function of HBV mice in the peripheral blood,spleen and liver.4.All statistical analyses were based on a two-tailed hypothesis tests with a significance level of P<0.050.Results1.CHB without treated showed that the mean frequency of circulating CXCR5+CD8+T cells in CHB group was significantly higher than that in the HC group(P<0.050).Longitudinal study showed that the mean frequency of circulating CXCR5+CD8+T cells in complete response group(CR)group was significantly higher than that in the non-complete response group(NCR)group after telbivudine therapy(at 0 weeks,P=0.001;at 24 weeks,P==0.021:at 48 weeks,P=0.009).2.QPCR quantitative detect showed that intrahepatic CXCL13 higher expression(P<0.050)than healthy volunteers(HC)and are positively related to ALT.3.CXCR5+CD8+T cells expressing higher activation marker CD38,CD69 and HLADR(P<0.050;P<0.050;P<0.050)than CD8+T cells and CXCR5-CD8+T cells.CXCR5+CD8+T cells both secrete higher IFN-γ and interleukin-21(IL-21)compared with CD8 and CXCR5-CD8+T group(P<0.050;P<0.050),but secrete lower Granzyme B and with weak cytotoxic(P<0.050;P<0.050)than CD8+T cells and CXCR5-CD8+T cells.4.CXCR5+CD8+T cells in Chronic HBV infection express higher proportion inhibitory receptors PD1,CTLA4,while activate receptor CD38 expression lower,HLADR expression increased(P<0.050;P<0.050;P<0.050;P<0.050)than HC.CXCR5+CD8+T cells in Chronic hepatitis B patients secrete higher Granzyme B,IL-21,but lower IFN-γ(P<0.050;P<0.050;P<0.050)compared with HC.5.IL-21 promote CXCR5+CD8+T cells secrete higher IFN-γ during health and chronic HBV infected,while suppress PD1 expression on health,and has no effect on chronic HBV infection(P<0.050;P<0.050;P<0.050),anti-PD1 also can promote CXCR5+CD8+T cells secrete IFN-γ(P<0.050).6.The CXCR5+CD8+T cells frequency of spleen is significantly higher than the peripheral blood and liver in HBV mice(P<0.010;P<0.050).ConclusionsCXCR5+CD8+T cells play an important role of antiviral in chronic HBV infection.