Expression of Capsid Proteins and Nonstructural Proteins of Waterfowl Parvoviruses in Escherichia coli and Their Use in Serological Assay and Development of Subunit Vaccine

• Main Authors: Chia-Ying Wang, 汪佳穎
• Other Authors: Poa-Chun Chang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/98574173166695977651

碩士 === 國立中興大學 === 獸醫微生物學研究所 === 93 === The infection of waterfowl parvovirus could lead to high mortality and morbidity of ducklings and goslings and cause severe economic losses. While there are a number of methods available for detection of antibodies against waterfowl parvoviruses, none is able to differentiate responses against the capsid and nonstructural proteins. Moreover, current vaccination program is using the traditional passive immunization, but it is difficult to evalute the titers of antibody of the sera used for vaccination. Both field infection and vaccination using live virus elicit antibodies against the capsid and nonstructural protein and it is impossible to differentiate field-infected from vaccinated birds. To enable this, the capsid and nonstructural proteins of goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV) were expressed in E. coli. These proteins were purified and used as antigens in Western blotting assays and as subunit vaccine. The goal of this study can be divided into two parts; the first part is using Western blotting assays to evalute the prevalence of antibody against GPV and MDPV in the field. The second part is to develop a subunit vaccine for the control of GPV and MDPV. Western blotting assays showed that 94.7% of the goose and 90.0% of the duck sera collected from the field contained antibodies against GPV or MDPV. Moreover, these sera could be classified into distinct groups based on differences in patterns of Western blot reactivity. These different patterns might indicate different stages in infection. Western blotting assays of sera collected from experimentally infected ducks showed that antibodies against the nonstructural protein appeared first after infection, followed by antibodies against the capsid protein. It was concluded that the recombinant capsid and nonstructural proteins might serve as useful antigens for assays for antibodies against GPV and MDPV. Moreover, because these assays could discriminate between antibodies against the nonstructural protein and those against the capsid protein, they may be useful in differentiating vaccinated from infected birds when recombinant capsid protein is used as the vaccine. Vaccination of ducks by recombinant VP3, VP1N and NS showed that three recombinant proteins could provide partial protection against the challenge of GPV and MDPV, but this result needs to be confirmed by further experiments.