| Summary: | 碩士 === 國立中興大學 === 微生物暨公共衛生學研究所 === 98 === Infectious bursal disease (IBD), also known as Gumboro disease is a highly contagious, immunosuppressive disease of immature chickens caused by a birnavirus, IBD virus (IBDV) which is responsible for major economic losses in the poultry industry worldwide. The VP2 of IBDV is a structural protein and related to the host-protective immune response. The objective of this study was to compare the efficiency of commercial ELISA coated with whole IBDV and home-made ELISA coated with VP2 protein on the detection of anti-IBDV antibodies in chickens vaccinated with VP2 DNA or subunit vaccine. The VP2 protein was expressed in E.coli and purified by an anti-His tag purification kit. After optimization of the VP2 ELISA, the combination of 500 ng of VP2 protein, 100X dilution of primary anti-IBDV antibody, and 1500X dilution of secondary anti-chicken-IgG antibody was selected to have ratios of positive control readings and negative control readings (P/N) as high as 8. Sera from chickens received VP2 DNA vaccine, VP243 DNA vaccine, VP2 protein vaccine, or IBDV challenge were tested. Prior to challenge, the S/N (ratio of sample readings and negative control readings) ratios of VP2 ELISA were significantly higher than those of commercial ELISA with sera in chicken vaccinated with VP2 protein. With sera from chicken vaccinated with VP243 DNA vaccine, the S/NC ratios of VP2 ELISA were significantly lower than those of commercial ELISA. After challenge, the similar results were also observed. Nevertheless, only VP2 and VP243 DNA vaccines provided more than 80 % protection in chickens against IBDV challenge. The results indicated that ELISA coated with VP2 protein might be feasible for evaluation of anti-IBDV antibody titers in chicken vaccinated with VP2 protein. However, the antibody titers measured by VP2 ELISA is not correlated to the protection efficacy.
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