Single chain antibody fragment against the horizontal transmission of white spot syndrome virus in Penaeus vannamei
Date Issued
2015
Date
2015
Author(s)
Chen, Lung-Yi
Abstract
Shrimp farming is very important in aquaculture today. According to Food and Agriculture Organization of the United Nations (FAO), the production of global shrimp aquaculture nowadays accounts for about 15 percent of global aquaculture output value. However, numerous disease outbreaks have caused huge economic losses, among them, one of the most threatening pathogens is the white spot syndrome virus (WSSV). WSSV can cause up to 100% mortality within 10 days in shrimp farms, and to date, no therapeutics has been published to effectively inhibit WSSV infection in the field. A single chain antibody fragment against WSSV, sAP-1 (derived from AP-1, a monoclonal antibody against WSSV), was constructed by Transcending Biotechnologies Inc. (U.S.A.). sAP-1 could protect shrimps from the infection of WSSV in virus challenge experiments through injection, indicating the possibility of substituting the use of AP-1. In order to produce secreted sAP-1 more economic and meet the requirements for food safety, a probiotic, B. megaterium, was used for sAP-1 expression. Our goal in this study is to test the efficiency of sAP-1 against WSSV by oral administration. The results showed that sAP-1 can’t be expressed by B. megaterium, but the production of sAP-1 in E. coli expression system can be optimized and increased. In the oral challenge experiments, WSSV could infect shrimps via ingestion more efficient than via immersion, the mortality and the viral loads of shrimps decreased when fed with additional sAP-1. According to the results of ELISA (sAP-1 can bind to VP28 in competition assay with AP-1 as competitor) and superoxide anion production (sAP-1 doesn’t stimulate shrimp’s immune system), sAP-1 may interfere the attachment between WSSV and cells by binding to VP28.
Subjects
white spot syndrome virus
B. megaterium expression system
E. coli expression system
neutralizing antibody
single-chain variable fragment
Type
thesis
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