title: Heat shock protein 70 enhances mucosal immunity against human norovirus when coexpressed from a vesicular stomatitis virus vector.
abstract: Human norovirus (NoV) accounts for 95% of nonbacterial gastroenteritis worldwide. Currently, there is no vaccine available to combat human NoV as it is not cultivable and lacks a small-animal model. Recently, we demonstrated that recombinant vesicular stomatitis virus (rVSV) expressing human NoV capsid protein (rVSV-VP1) induced strong immunities in mice (Y. Ma and J. Li, J. Virol. 85:2942-2952, 2011). To further improve the safety and efficacy of the vaccine candidate, heat shock protein 70 (HSP70) was inserted into the rVSV-VP1 backbone vector. A second construct was generated in which the firefly luciferase (Luc) gene was inserted in place of HSP70 as a control for the double insertion. The resultant recombinant viruses (rVSV-HSP70-VP1 and rVSV-Luc-VP1) were significantly more attenuated in cell culture and viral spread in mice than rVSV-VP1. At the inoculation dose of 1.0 × 10(6) PFU, rVSV-HSP70-VP1 triggered significantly higher vaginal IgA than rVSV-VP1 and significantly higher fecal and vaginal IgA responses than rVSV-Luc-VP1, although serum IgG and T cell responses were similar. At the inoculation dose of 5.0 × 10(6) PFU, rVSV-HSP70-VP1 stimulated significantly higher T cell, fecal, and vaginal IgA responses than rVSV-VP1. Fecal and vaginal IgA responses were also significantly increased when combined vaccination of rVSV-VP1 and rVSV-HSP70 was used. Collectively, these data indicate that (i) insertion of an additional gene (HSP70 or Luc) into the rVSV-VP1 backbone further attenuates the VSV-based vaccine in vitro and in vivo, thus improving the safety of the vaccine candidate, and (ii) HSP70 enhances the human NoV-specific mucosal and T cell immunities triggered by a VSV-based human NoV vaccine.
  
  
  OBJECTIVE
  Human norovirus (NoV) is responsible for more than 95% of acute nonbacterial gastroenteritis worldwide. Currently, there is no vaccine for this virus. Development of a live attenuated vaccine for human NoV has not been possible because it is uncultivable. Thus, a live vector-based vaccine may provide an alternative vaccine strategy. In this study, we developed a vesicular stomatitis virus (VSV)-based human NoV vaccine candidate. We constructed rVSV-HSP70-VP1, coexpressing heat shock protein (HSP70) and capsid (VP1) genes of human NoV, and rVSV-Luc-VP1, coexpressing firefly luciferase (Luc) and VP1 genes. We found that VSVs with a double gene insertion were significantly more attenuated than VSV with a single VP1 insertion (rVSV-VP1). Furthermore, we found that coexpression or coadministration of HSP70 from VSV vector significantly enhanced human NoV-specific mucosal immunity. Collectively, we developed an improved live vectored vaccine candidate for human NoV which will be useful for future clinical studies.
authors.affiliation: Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Yuanmei
authors.initials: Y
authors.lastname: Ma
authors.forename: Yue
authors.initials: Y
authors.lastname: Duan
authors.forename: Yongwei
authors.initials: Y
authors.lastname: Wei
authors.forename: Xueya
authors.initials: X
authors.lastname: Liang
authors.forename: Stefan
authors.initials: S
authors.lastname: Niewiesk
authors.forename: Michael
authors.initials: M
authors.lastname: Oglesbee
authors.forename: Jianrong
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology; D005260:Female; D041981:Gastrointestinal Tract / Q000276:immunology; D005822:Genetic Vectors; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology*; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D029322:Norovirus / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014621:Vagina / Q000276:immunology; D018116:Vesiculovirus / Q000235:genetics*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D036022:Capsid Proteins; D018840:HSP70 Heat-Shock Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014765:Viral Vaccines