Activation of intrahepatic CD4 + CXCR5 + T and CD19 + B cells is associated with viral clearance in a mouse model of acute hepatitis B virus infection

// Xiao-Fei Song 1,* , Ting-Ting Hu 1,* , Yu Lei 1,* , Hu Li 1 , Li Zhang 1 , Miao Zhang 1 , Bin Liu 1 , Min Chen 1 , Huai-Dong Hu 1 , Hong Ren 1 and Peng Hu 1 1 Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China * These authors have contributed equally to this study Correspondence to: Peng Hu, email: // Keywords : acute hepatitis B; hydrodynamic injection; intrahepatic lymphocytes; viral clearance; Immunology and Microbiology Section; Immune response; Immunity Received : January 08, 2016 Accepted : July 06, 2016 Published : July 18, 2016 Abstract The role of immunity in the pathogenesis of acute hepatitis B virus (HBV) infection is poorly understood. The purpose of this research was to define the intrahepatic immune factors responsible for viral clearance during acute HBV infection. The model of acute HBV infection was established by hydrodynamically transfecting mice with pCDNA3.1-HBV1.3 plasmids which contained a supergenomic HBV1.3-length transgene. The frequency of CD4 + CXCR5 + T cells, CD19 + B cells and their surface molecules in livers, spleens and peripheral blood were detected using flow cytometry. The lymphomononuclear cells isolated from the livers of transfected mice were further stimulated by HBc-derived peptides and then the frequency and cytokine secretion of HBV-specific CD4 + CXCR5 + T cells were detected. We found that the frequency of CXCR5 + in CD4 + T cells was specifically increased; the expression of PD-1 was decreased while the expression of ICOS was increased on intrahepatic CD4 + CXCR5 + T cells. Although the frequency of CD19 + B cells was not affected, the expression of PDL-1, ICOSL and IL-21R on B cells was increased in the livers of mice. The frequency of HBV-specific CD4 + CXCR5 + T cells and the production of IL-21 by intrahepatic CD4 + CXCR5 + T cells of mice with acute HBV infection were increased after stimulation. Furthermore, the expression of function-related molecules of intrahepatic CD4 + CXCR5 + T, including Bcl-6, CXCR5, IL-6, IL-6R, IL-21 and IL-4 in the liver was increased during acute HBV infection. In conclusion, the activation of intrahepatic CD4 + CXCR5 + T cells and B cells was associated with the clearance of HBV during acute infection.