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Journal of Immunology Research
Volume 2015, Article ID 762426, 12 pages
http://dx.doi.org/10.1155/2015/762426
Research Article

Comparative Immunogenicity in Rabbits of the Polypeptides Encoded by the 5′ Terminus of Hepatitis C Virus RNA

1Latvian Biomedical Research and Study Center, Ratsupites Street 1, Riga LV-1067, Latvia
2N. F. Gamaleja Research Center of Epidemiology and Microbiology, Gamaleja Street 18, Moscow 123098, Russia
3Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels Väg 16, 17177 Stockholm, Sweden
4Riga Stradins University, Dzirciema Street 16, Riga LV-1007, Latvia

Received 22 July 2015; Accepted 29 September 2015

Academic Editor: Masha Fridkis-Hareli

Copyright © 2015 Irina Sominskaya et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Recent studies on the primate protection from HCV infection stressed the importance of immune response against structural viral proteins. Strong immune response against nucleocapsid (core) protein was difficult to achieve, requesting further experimentation in large animals. Here, we analyzed the immunogenicity of core aa 1–173, 1–152, and 147–191 and of its main alternative reading frame product F-protein in rabbits. Core aa 147–191 was synthesized; other polypeptides were obtained by expression in E. coli. Rabbits were immunized by polypeptide primes followed by multiple boosts and screened for specific anti-protein and anti-peptide antibodies. Antibody titers to core aa 147–191 reached 105; core aa 1–152, 5 × 105; core aa 1–173 and F-protein, 106. Strong immunogenicity of the last two proteins indicated that they may compete for the induction of immune response. The C-terminally truncated core was also weakly immunogenic on the T-cell level. To enhance core-specific cellular response, we immunized rabbits with the core aa 1–152 gene forbidding F-protein formation. Repeated DNA immunization induced a weak antibody and sustained proliferative response of broad specificity confirming a gain of cellular immunogenicity. Epitopes recognized in rabbits overlapped those in HCV infection. Our data promotes the use of rabbits for the immunogenicity tests of prototype HCV vaccines.