title: Search for potential target site of nucleocapsid gene for the design of an epitope-based SARS DNA vaccine.
abstract: It is believed today that nucleocapsid protein (N) of severe acute respiratory syndrome (SARS)-CoV is one of the most promising antigen candidates for vaccine design. In this study, three fragments [N1 (residues: 1-422); N2 (residues: 1-109); N3 (residues: 110-422)] of N protein of SARS-CoV were expressed in Escherichia coli and analyzed by pooled sera of convalescence phase of SARS patients. Three gene fragments [N1 (1-1269 nt), N2 (1-327 nt) and N3 (328-1269 nt)-expressing the same proteins of N1, N2 and N3, respectively] of SARS-N were cloned into pVAX-1 and used to immunize BALB/c mice by electroporation. Humoral (by enzyme-linked immunosorbent assay, ELISA) and cellular (by cell proliferation and CD4(+):CD8(+) assay) immunity was detected by using recombinant N1 and N3 specific antigen. Results showed that N1 and N3 fragments of N protein expressed by E. coli were able to react with sera of SARS patients but N2 could not. Specific humoral and cellular immunity in mice could be induced significantly by inoculating SARS-CoV N1 and N3 DNA vaccine. In addition, the immune response levels in N3 were significantly higher for antibody responses (IgG and IgG1 but not IgG2a) and cell proliferation but not in CD4(+):CD8(+) assay compared to N1 vaccine. The identification of antigenic N protein fragments has implications to provide basic information for the design of DNA vaccine against SARS-CoV. The present results not only suggest that DNA immunization with pVax-N3 could be used as potential DNA vaccination approaches to induce antibody in BALB/c mice, but also illustrates that gene immunization with these SARS DNA vaccines can generate different immune responses.
authors.affiliation: Laboratory Animal Medicine, College of Veterinary Medicine and KRF Zoonotic Disease Priority Research Institute, Seoul National University, Gwanak-Gu, Seoul, Republic of Korea.
authors.forename: Noton Kumar
authors.initials: NK
authors.lastname: Dutta
authors.forename: Kaushiki
authors.initials: K
authors.lastname: Mazumdar
authors.forename: Byoung-Hee
authors.initials: BH
authors.lastname: Lee
authors.forename: Min-Won
authors.initials: MW
authors.lastname: Baek
authors.forename: Dong-Jae
authors.initials: DJ
authors.lastname: Kim
authors.forename: Yi-Rang
authors.initials: YR
authors.lastname: Na
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Hyun-Kyoung
authors.initials: HK
authors.lastname: Lee
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kariwa
authors.forename: Le Quynh
authors.initials: le Q
authors.lastname: Mai
authors.forename: Jae-Hak
authors.initials: JH
authors.lastname: Park
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D002460:Cell Line; D049109:Cell Proliferation; D000939:Epitopes / Q000276:immunology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D019251:Nucleocapsid / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
chemical_list: D000906:Antibodies; D000939:Epitopes; D019444:Vaccines, DNA; D014765:Viral Vaccines