Individual expression and processing of hepatitis C virus E1/E2 epitopes-based DNA vaccine candidate in healthy humans’ peripheral blood mononuclear cells

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Purpose: The development and study of hepatitis C virus (HCV) vaccine candidates' individualized responses are of great importance.Here we report on an HCV DNA vaccine candidate based on selected envelope (E1/E2) epitopes.Besides, we assessed its expression and processing in human peripheral blood mononuclear cells (PBMCs) and in vivo cellular response in mice.Materials and Methods: HCV E1/E2 DNA construct (EC) was designed.The antigen expression of EC was assayed in PBMCs of five HCV-uninfected donors via a real-time quantitative polymerase chain reaction.Serum samples from 20 HCV antibody-positive patients were used to detect each individual PBMCs expressed antigens via enzyme-linked immunosorbent assay.Two groups, five Swiss albino mice each, were immunized with the EC or a control construct.The absolute count of lymph nodes' CD4 + and CD8 + T-lymphocytes was assessed.Results: Donors' PBMCs showed different levels of EC expression, ranging between 0.83-2.61-fold in four donors, while donor-3 showed 34.53-fold expression.The antigens expressed in PBMCs were significantly reactive to the 20 HCV antibody repertoire (all p=0.0001).All showed comparable reactivity except for donor-3 showing the lowest reactivity level.The absolute count % of the CD4 + T-cell significantly increased in four of the five EC-immunized mice compared to the control group (p=0.03).No significant difference in CD8 + T-cells % was observed (p=0.89).Conclusion: The inter-individual variation in antigen expression and processing dominance was evident, showing independence in individuals' antigen expression and reactivity levels to antibodies.The described vaccine candidate might result in a promising natural immune response with a possibility of CD4 + T-cell early priming.