Hu H, Lu X, Tao L, Bai B, Zhang Z, Chen Y, Zheng F, Chen J, Chen Z, Wang H
Induction of specific immune responses by SARS-CoV spike DNA vaccine with or without interleukin-2 immunization using different immune routes in mice. [JOURNAL ARTICLE]
Clin Vaccine Immunol 2007 May 9.
DNA vaccines induce humoral and cellular immune responses in animal models and humans. To analyze the immunogenicity of the SARS-CoV spike DNA vaccine and the immunoregulatory activity of interleukin-2 (IL-2), DNA vaccine plasmids pcDNA-S and pcDNA-IL2 were constructed, and inoculated into BALB/c mice with or without pcDNA-IL2 using 3 different immunization routes (intramuscularly, by electroporation, or orally using live-attenuated Salmonella typhimurium). Cellular and humoral immune responses were assessed by ELISA, lymphocyte proliferation assays, ELISPOT, and FACS. Results showed that specific humoral and cellular immunities in mice could be induced by inoculating with SARS-CoV spike DNA vaccine alone or co-inoculating with IL-2-expressing plasmids. In addition, the immune response levels in the co-inoculation groups were significantly higher than those in the spike DNA vaccine alone groups. The comparison between the 3 vaccination routes indicated that oral vaccination evoked a vigorous T cell response and a weak antibody response predominantly with subclass IgG2a. However, intramuscular immunization evoked a vigorous antibody response and a weak T cell response, and vaccination with electroporation evoked a vigorous antibody response with predominant subclass IgG1 and a moderate T cell responses. Our findings showed that the S DNA vaccine had a good immunogenicity, and could induce specific humoral and cellular immunities in BALB/c mice, while IL-2 played an immunoadjuvant role and enhanced the humoral and cellular immune responses. Different vaccination routes also evoke distinct immune responses. This study provides basic information for the design of DNA vaccines against SARS-CoV.
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