| Summary: | 碩士 === 國立臺灣大學 === 獸醫學研究所 === 90 === Riemerella anatipestifer (RA) causes worldwide infectious serotitis of waterfowls, which very often leads to the high mortality of ducklings under the age of 8 weeks. Consequently, it may bring about a serious economic loss. For an effective approach against RA infection, it is necessary to take into account the very phenomenon that there is only little or none cross protection found in 20 serovars. Therefore, a cross-protective vaccine would be the most convienient and economical strategy, as we try to work out as the follows: The vapD1 (298bp) is amplified by PCR from pCFC1 or pCFC2 plasmid of RA and then ligated with the pRSET A and pcDNA3.1(+) vector which were designated as pVapD and pcVapD3.1 individually. The pVapD plasmid is transformed into E. coli BL21(DE3)pLysS. This transformation expresses an 11kDa of VapD1 protein and serves as the subunit vaccine. The recombinant DNA plasmid of pcVapD3.1 is transformed into E. coli JM109. In contrast to the subunit and DNA vaccine, there is a 10% formalin treated bacterin of serotype 2 RA (CF27). After two injections of different kinds of vaccines at a two-week interval, ducks were challenged by the homologous strain of serotype 2 RA (CF27). Then we came to record the mortality of ducks for the calculation of Protection index (PI) value. We found that The PI value of subunit and the DNA vaccine of VapD1 and bacterin were 12.5, 25 and 100 respectively. This proves that the vapD1 protein and the pcVapD3.1 recombinant plasmid cannot induce sufficient protection effects in ducks to prevent them from the attack of serotype 2 RA.
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