Analysis of HBV-Specific CD4 T-cell Responses and Identification of HLA-DR-Restricted CD4 T-Cell Epitopes Based on a Peptide Matrix

CD4 T cells play important roles in the pathogenesis of chronic hepatitis B. As a versatile cell population, CD4 T cells have been classified as distinct functional subsets based on the cytokines they secreted: for example, IFN-gamma for CD4 T helper 1 cells, IL-4 and IL-13 for CD4 T helper 2 cells, IL-21 for CD4 T follicular helper cells, and IL-17 for CD4 T helper 17 cells. Analysis of hepatitis B virus (HBV)-specific CD4 T cells based on cytokine secretion after HBV-derived peptides stimulation could provide information not only about the magnitude of HBV-specific CD4 T-cell response but also about the functional subsets of HBV-specific CD4 T cells. Novel approaches, such as transcriptomics and metabolomics analysis, could provide more detailed functional information about HBV-specific CD4 T cells. These approaches usually require isolation of viable HBV-specific CD4 T cells based on peptide-major histocompatibility complex-II multimers, while currently the information about HBV-specific CD4 T-cell epitopes is limited. Based on an HBV-derived peptide matrix, a method has been developed to evaluate HBV-specific CD4 T-cell responses and identify HBV-specific CD4 T-cell epitopes simultaneously using peripheral blood mononuclear cells samples from chronic HBV infection patients.