Mice Antibody Response to Conserved Nonadjuvanted Multiple Antigenic Peptides Derived from E1/E2 Regions of Hepatitis C Virus

Abstract

Synthetic peptides are one of the hepatitis C virus (HCV)-specific small molecules that have antiviral activity and represent a target for HCV vaccine. This study aims to determine the lowest concentration of adjuvanted and non-adjuvanted (multiple antigenic peptide [MAP]) form of three conserved HCV envelope peptides that can induce murine immunogenic responses and evaluate the neutralization capacities of the generated antibodies (Abs) against HCV in cultured Huh7.5 cells. In this study, three HCV synthetic peptides, E1 peptide (a.a 315-323) and E2 peptides (a.a 412-419 and a.a 516-531) were synthesized. Female Balb/c mice were immunized with different concentration of either adjuvanted linear peptides or nonadjuvanted MAP peptides to determine the lowest dose that generates Ab responses enough to confer viral neutralization in vitro. The humoral responses targeting these peptides in immunized mice sera were measured by enzyme-linked immunosorbent assay (ELISA). Viral neutralization capacities of the generated mice Abs were assessed using Huh7.5 cells infected with the HCVcc infectious system (J6/JFH-1). The results of this study showed that the MAPs induce higher Ab titers than adjuvanted linear peptides after 4 weeks of immunization (p = 0.003). The viral neutralization experiments showed that the immunized mice sera contain anti E1/E2 Abs that blocked HCVcc (J6/JFH-1) entry into Huh7.5 cells. In conclusion, the three HCV envelope MAP peptides are more immunogenic and produce higher neutralizing Abs than linear peptides; therefore, they can be essential components for HCV vaccine.

Keywords: HCV; neutralizing antibodies; synthetic peptides.