A self-adjuvanting multiepitope immunogen that induces a broadly cross-reactive antibody to hepatitis C virus

Abstract

We describe a peptide-based strategy for HCV vaccine design that addresses the problem of variability in hypervariable region 1 (HVR1). Peptides representing antibody epitopes of HVR1 from genotype 1a were synthesized and incorporated into multideterminant immunogens that also included lipid moieties and helper T (T h ) cell epitopes. Mice inoculated with these polyepitopes generated strong antibody responses. Antibody titers were highest in mice inoculated with polyepitope immunogens which contained the lipid moiety dipalmitoyl-S-glyceryl cysteine (Pam2Cys). Antisera were tested for their potential to neutralize HCV by 3 currently available assays. Antibodies elicited in mice by the polyepitope-based vaccine candidates were able to (1) bind to E2 expressed on the surface of E1/E2-transfected human embryonic kidney (HEK) 293T cells, (2) H epatitis C virus (HCV) is a human pathogen that has major global significance. It is estimated that 170 million people worldwide and more than 10% of the population in some countries are infected with HCV. 1 A range of illnesses have been associated with HCV including acute and chronic hepatitis, cirrhosis of the liver, and HCC. Hepatitis C infection is now the leading indication for liver transplantation in countries such as the United States. In the absence of a vaccine, treatment is confined to the use of the combination of interferon-␣ and pegylated interferon-␣ together with the antiviral drug ribavirin. [2][3][4][5] The development of a vaccine against HCV could prevent HCV-associated diseases. However, there are 2 major impediments to the development of a HCV vaccine: the vast diversity of viral genotypes and quasispecies and the complex nature of the immune response required to clear infection. Antibodies directed to epitopes in the viral glycoprotein E2 (including HVR1) are neutralizing. [6][7][8][9][10][11][12][13][14] Further evidence supporting the protective role of neutralizing antibody was recently highlighted by the demonstration of the presence of neutralizing antibodies in immune globulin prepared from anti-HCV serum. 13 This immune globulin protected chimpanzees from infection with HCV genotypes 1a and 2a, 13 strengthening the argument that neutralizing antibodies can be cross-protective. In addition, it has been shown that it is possible to prevent entry of retroviral particles pseudotyped with the

Characterization of a hepatitis C virus-like particle vaccine produced in a human hepatocyte-derived cell line

“…The recombinant HCV E2 protein was produced using pCDNA3.tpaE2-661myc plasmid (provided by Dr Charles Rice, Rockefeller University, NY, USA) as described previously (Torresi et al, 2007).…”

Progress in the development of preventive and therapeutic vaccines for hepatitis C virus

“…Distinct neutralizing antibody epitopes have been identified in hypervariable region 1 (HVR1) of the E2 protein [37,38,62,88,124] and in the region downstream of HVR1, including the binding sites for the putative HCV receptor, CD81 [8,53,62,68,84,143,144]. Also, epitopes in the amino-terminus of HVR1 may induce neutralising antibody responses that are associated with self-limiting hepatitis C infection [160].…”

Synthetic peptide vaccines

“…Однако бывает, что ни один из видов лабораторных животных не подвержен исследуемому заболеванию. В таких случаях в качестве моделей используют иммунодефицитных (SCID) мышей с ксенотрансплантированными клетками или тканями человека (для малярии -SCID мыши с пересаженными эритроцитами человека [91], для гепатита С -SCID мыши с пересаженной тканью печени человека [92,93]), либо исследователи ограничиваются тестированием протективности иммунного ответа на клеточных культурах. Например, тестирование вируснейтрализующей активности антител, вырабатываемых в ответ на антигены вируса гепатита С, проводят в экспериментах по блокированию проникновения самого вируса или вирусоподобных частиц, несущих на поверхности оболочечные белки ВГС, в первичные гепатоциты или в клетки гепатомы в культуре [94].…”