Clin Exp Vaccine Res.  2023 Jan;12(1):47-59. 10.7774/cevr.2023.12.1.47.

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

• Nadeem R
• Maghraby AS
• Abd-Elshafy DN
• Barakat AB
• Bahgat MM

• KMID: 2552326
• DOI: http://doi.org/10.7774/cevr.2023.12.1.47

Abstract

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.

Keyword

Hepatitis C virus; DNA vaccines; Human peripheral blood mononuclear cells; Individuality; Envelope protein