title: Construction of a eukaryotic expression plasmid encoding partial S gene fragments of the SARS-CoV and its potential utility as a DNA vaccine.
abstract: The spike (S) protein, a main surface antigen of the SARS coronavirus (SARS-CoV), is considered to be one of the most important protective antigen candidates for targets for vaccine design against the virus. In this study, a secreted recombinant expression plasmid, pVAX-S1, encoding the partial S protein with a signal peptide, was constructed and used to immunize BALB/c mice through electroporation. It was demonstrated that the eukaryotic expression vector pVAX-S1 was successfully constructed by restriction enzyme and sequence analysis. The expressed protein could be detected specifically by Western blot analysis. The serum IgG level of the vaccine group mice was significantly higher than that of the corresponding control group at day 14 after vaccination (P < 0.05). The vaccine group demonstrated significantly higher S1 protein lymphocyte proliferation index (LPI) than the control groups (P < 0.05). Furthermore, in the experimental group, a decrease in the ratio of CD4(+) to CD8(+) T-lymphocytes and an increase level of IFN-gamma in serum were observed. However, interleukin-4 (IL-4) was not detectable in two groups. These results strongly demonstrated that the pVAX-S1 plasmid could induce humoral and cellular immune responses in mice, and may be a potential candidate for a DNA vaccine against the SARS coronavirus.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, People's Republic of China.
authors.forename: Hongxuan
authors.initials: H
authors.lastname: He
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.forename: Ximing
authors.initials: X
authors.lastname: Qin
authors.forename: Wenbo
authors.initials: W
authors.lastname: Xu
authors.forename: Yifei
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Liu
authors.forename: Xingyou
authors.initials: X
authors.lastname: Liu
authors.forename: Sheng
authors.initials: S
authors.lastname: Xiong
authors.forename: Jiuxiang
authors.initials: J
authors.lastname: Li
authors.forename: Meiying
authors.initials: M
authors.lastname: Zhang
authors.forename: Mingxing
authors.initials: M
authors.lastname: Duan
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D016516:CD4-CD8 Ratio; D049109:Cell Proliferation; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000097:blood; D015847:Interleukin-4 / Q000097:blood; D018655:Lymphocyte Count; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D011994:Recombinant Proteins; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics* / Q000276:immunology*; D064370:Spike Glycoprotein, Coronavirus; D013601:T-Lymphocytes / Q000276:immunology; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000276:immunology*; D014765:Viral Vaccines
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D064370:Spike Glycoprotein, Coronavirus; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus; D015847:Interleukin-4; D007371:Interferon-gamma