Humoral and cellular immune responses induced by 3a DNA vaccines against severe acute respiratory syndrome (SARS) or SARS-like coronavirus in mice.
Vaccine development for severe acute respiratory syndrome coronavirus (SARS-CoV) has mainly focused on the spike (S) protein. However, the variation of the S gene between viruses may affect the efficacy of a vaccine, particularly for cross-protection against SARS-like CoV (SL-CoV). Recently, a more conserved group-specific open reading frame (ORF), the 3a gene, was found in both SARS-CoV and SL-CoV. Here, we studied the immunogenicity of human SARS-CoV 3a and bat SL-CoV 3a DNA vaccines in mice through electroporation immunization followed by enzyme-linked immunosorbent, enzyme-linked immunospot, and flow cytometry assays. Our results showed that high levels of specific humoral responses were induced by SARS-CoV 3a and SL-CoV 3a DNA vaccines. Furthermore, a strong Th1-based cellular immune response was stimulated by both DNA vaccines. The vaccines stimulated gamma interferon production mainly by CD8(+) T cells and interleukin-2 (IL-2) mainly by CD4(+) T cells. Of interest, the frequency of IL-2-positive cells elicited by the SARS-CoV 3a DNA vaccine was significantly higher than that elicited by the SL-CoV 3a DNA vaccine. In summary, our study provides a reference for designing cross-protective DNA vaccines based on the group-specific ORFs of CoVs.
Lu
Baojing
B
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
Tao
Ling
L
Wang
Ting
T
Zheng
Zhenhua
Z
Li
Bao
B
Chen
Ze
Z
Huang
Yi
Y
Hu
Qinxue
Q
Wang
Hanzhong
H
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D005260:Female; D005434:Flow Cytometry; D007124:Immunoenzyme Techniques / Q000379:methods; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D019444:Vaccines, DNA / Q000276:immunology*; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology*; D000086082:Viroporin Proteins
C487105:3a protein, SARS-CoV; D000914:Antibodies, Viral; D007376:Interleukin-2; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D014764:Viral Proteins; D000086082:Viroporin Proteins; D007371:Interferon-gamma