| Summary: | 碩士 === 國立成功大學 === 生物科技研究所碩博士班 === 96 === Most piscatorial subunit vaccines are produced by E. coli expression system that is easy to use. However, this conventional oral vaccine can not add additional adjuvant
to induce effective innate immunity, which may result in a lower protective immune response.
Previously, we have demonstrated that Vibrio anguillarum could induce fish innate immunity and could be used as an effective adjuvant. By using V. anguillarum as expression host to synthesize specific antigen and use the whole Vibrio as component of an oral vaccine, it is expected to induce both innate and adaptive immunity simultaneously, thus could confer better protective efficacy.
First we obtained NNV coat protein gene and expressed in V. anguillarum and E. coli respectively. They were then encapsulated in Artemia for the following study. After administrating to grouper larvae, the immune stimulatory effects of V. anguillarum and E. coli were evaluated by analyzing the gene expression levels of TNF-α, IL-1β and Mx genes at 4 day post immunization (DPI), and the
antigen-specific antibody production at 7 DPI respectively, and the protective efficacy of these two vaccines were then evaluated by challenge of 1×105.5
TCID50/fish of NNV at 7 DPI.
The results showed V. anguillarum can induce the Mx mRNA expression in brain at 2nd day after administration. Although the amount of NNV coat protein in V. anguillarum only reached 1~2 % of the total protein, and was much lower than that at least 10 % as in E. coli, however, the new subunit vaccines can elicit higher antibody titer at 7 DPI and provide much better protective efficacy than that of E. coli vaccine, revealing the potential of using Vibrio expression system for the production of piscatorial subunit vaccines.
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