title: Recombinant Dengue 2 Virus NS3 Helicase Protein Enhances Antibody and T-Cell Response of Purified Inactivated Vaccine.
abstract: Dengue virus purified inactivated vaccines (PIV) are highly immunogenic and protective over the short term, but may be poor at inducing cell-mediated immune responses and long-term protection. The dengue nonstructural protein 3 (NS3) is considered the main target for T-cell responses during viral infection. The amino (N)-terminal protease and the carboxy (C)-terminal helicase domains of DENV-2 NS3 were expressed in E. coli and analyzed for their immune-potentiating capacity. Mice were immunized with DENV-2 PIV with and without recombinant NS3 protease or NS3 helicase proteins, and NS3 proteins alone on days 0, 14 and 28. The NS3 helicase but not the NS3 protease was effective in inducing T-cell responses quantified by IFN-γ ELISPOT. In addition, markedly increased total IgG antibody titer against virus antigen was seen in mice immunized with the PIV/NS3 helicase combination in the ELISA, as well as increased neutralizing antibody titer measured by the plaque reduction neutralization test. These results indicate the potential immunogenic properties of the NS3 helicase protein and its use in a dengue vaccine formulation.
authors.affiliation: Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America.
authors.forename: Monika
authors.initials: M
authors.lastname: Simmons
authors.affiliation: Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America.
authors.forename: Peifang
authors.initials: P
authors.lastname: Sun
authors.affiliation: Division of Viral Diseases, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Putnak
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003716:Dengue Virus / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D051379:Mice; D008811:Mice, Inbred DBA; D020365:RNA Helicases / Q000276:immunology; D011995:Recombination, Genetic; D012697:Serine Endopeptidases / Q000276:immunology; D015164:Vaccines, Inactivated / Q000276:immunology*; D017361:Viral Nonstructural Proteins / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000914:Antibodies, Viral; D007371:Interferon-gamma; D020365:RNA Helicases; D012697:Serine Endopeptidases; D015164:Vaccines, Inactivated; D017361:Viral Nonstructural Proteins; D014765:Viral Vaccines; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases