| Summary: | 碩士 === 國立屏東科技大學 === 獸醫學系所 === 102 === Chicken infectious anemia (CIA), caused by chicken anemia virus (CAV), mainly resulted in anemia, growth retardation and immune suppression in young chicks. The disease causes a significant economic loss to the poultry industry. Current vaccine strategies are based on the prevention of vertical transmission in breeder and giving maternal antibody to chicks against wild CAV infection. Vaccination should be performed at about 8-15 weeks of age to avoid the risk of CAV vaccine strain spread through the egg. However, the age between 3 weeks and 10 weeks is weak protection against CAV due to degradation of maternal antibody and lower titer of activated immunity. The purpose of this study is to develop an inactivated vaccine or subunit vaccine for using in breeder and chick stages. This study re-cloned CAV VP1/VP2 gene to pGEX-6P-1 expression vector, through restriction enzyme digestion and gel electrophoresis to confirm the DNA fragments as 1385 bp (VP1) and 651 bp (VP2), respectively. Subunit protein production using the prokaryotic expression system that could be identified by Western blotting with anti-GST monoclonal antibody and CAV positive sera proved that antigenicity by the MW of protein in 81 kDa (VP1) and 56 kDa (VP2). The expressed proteins were then purified by affinity chromatography column. On the other hand, a CAV strain was used to infect MDCC-MSB1 cell line. After evaluated the virus titer, the CAV supernatant was inactivated by binary ethyleneimide. CAV inactivated virus coupled VP1 and VP2 were conducted to animal trial. The experimental groups included inactivated virus group, VP1/VP2 recombinant protein group, and inactivated viruses coupled recombinant protein group. Animal experiments shown vaccination the CAV inactivated virus coupled VP1 and VP2 group or VP1 plus VP2 group had mild symptoms after challenge. Therefore, the two groups had better immune efficacy and are potentially for developing a CAV subunit vaccine.
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