title: Immunogenicity of Leishmania-derived hepatitis B small surface antigen particles exposing highly conserved E2 epitope of hepatitis C virus.
abstract: BACKGROUND
  Hepatitis C virus (HCV) infection is a major health problem worldwide, affecting an estimated 2-3 % of human population. An HCV vaccine, however, remains unavailable. High viral diversity poses a challenge in developing a vaccine capable of eliciting a broad neutralizing antibody response against all HCV genotypes. The small surface antigen (sHBsAg) of hepatitis B virus (HBV) has the ability to form highly immunogenic subviral particles which are currently used as an efficient anti-HBV vaccine. It also represents an attractive antigen carrier for the delivery of foreign sequences. In the present study, we propose a bivalent vaccine candidate based on novel chimeric particles in which highly conserved epitope of HCV E2 glycoprotein (residues 412-425) was inserted into the hydrophilic loop of sHBsAg.
  
  
  RESULTS
  The expression of chimeric protein was performed in an unconventional, Leishmania tarentolae expression system resulting in an assembly of particles which retained immunogenicity of both HCV epitope and sHBsAg protein. Direct transmission electron microscopy observation and immunogold staining confirmed the formation of spherical particles approximately 22 nm in diameter, and proper foreign epitope exposition. Furthermore, the sera of mice immunized with chimeric particles proved reactive not only to purified yeast-derived sHBsAg proteins but also HCV E2 412-425 synthetic peptide. Most importantly, they were also able to cross-react with E1E2 complexes from different HCV genotypes.
  
  
  CONCLUSIONS
  For the first time, we confirmed successful assembly of chimeric sHBsAg virus-like particles (VLPs) in the L. tarentolae expression system which has the potential to produce high-yields of properly N-glycosylated mammalian proteins. We also proved that chimeric Leishmania-derived VLPs are highly immunogenic and able to elicit cross-reactive antibody response against HCV. This approach may prove useful in the development of a bivalent prophylactic vaccine against HBV and HCV and opens up a new and low-cost opportunity for the production of chimeric sHBsAg VLPs requiring N-glycosylation process for their proper functionality and immunogenicity.
authors.affiliation: Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology UG-MUG, University of Gdańsk, A. Abrahama 58, 80-307, Gdańsk, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Czarnota
authors.affiliation: Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology UG-MUG, University of Gdańsk, A. Abrahama 58, Gdańsk, 80-307, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Tyborowska
authors.affiliation: Tri-City Academic Laboratory Animal Centre, Medical University of Gdańsk, Dębinki 1, Gdańsk, 80-211, Poland.
authors.forename: Grażyna
authors.initials: G
authors.lastname: Peszyńska-Sularz
authors.affiliation: Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology UG-MUG, University of Gdańsk, A. Abrahama 58, Gdańsk, 80-307, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Gromadzka
authors.affiliation: Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology UG-MUG, University of Gdańsk, A. Abrahama 58, 80-307, Gdańsk, Poland.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Bieńkowska-Szewczyk
authors.affiliation: Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology UG-MUG, University of Gdańsk, A. Abrahama 58, 80-307, Gdańsk, Poland. katarzyna.grzyb@biotech.ug.edu.pl.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Grzyb
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D005260:Female; D057809:HEK293 Cells; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007891:Leishmania / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D014614:Vaccines, Synthetic / Q000276:immunology; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000096:biosynthesis / Q000276:immunology; D014771:Virion / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000939:Epitopes; D006514:Hepatitis B Surface Antigens; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C091015:glycoprotein E2, Hepatitis C virus
keywords: HBV small surface antigen (sHBsAg); Hepatitis C virus (HCV); Leishmania tarentolae; VLP; Vaccine