文献类型：期刊文献

英文题名：An invasive and low virulent Edwardsiella tarda esrB mutant promising as live attenuated vaccine in aquaculture

作者：Yang, Weizheng[1];Wang, Lixia[1];Zhang, Lingzhi[1];Qu, Jiangbo[3];Wang, Qiyao[1,2];Zhang, Yuanxing[1,2]

机构：[1]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[2]Shanghai Collaborat Innovat Ctr Biomfg Technol, Shanghai 200237, Peoples R China;[3]TianYuan Aquat Prod Co Ltd, Yantai, Shandong, Peoples R China

年份：2015

卷号：99

期号：4

起止页码：1765

外文期刊名：APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

收录：;EI(收录号：20144900283157);WOS:【SCI-EXPANDED(收录号:WOS:000350028600020)】；

基金：This work was supported by grants from the Ministry of Agriculture of China (No. CARS-50 and nyhyzx-201303047), the National High Technology Research and Development Program of China (No. 2013AA093101), and Shanghai Rising-Star Program (No. 13QA1401000).

语种：英文

外文关键词：Edwardsiella tarda; T3SS; T6SS; esrB; Invasive phenotype; Vaccine

摘要：Edwardsiella tarda is a leading fish pathogen haunting worldwide aquaculture industry. In E. tarda, two-component system EsrA-EsrB positively regulates type III and VI secretion systems (T3SS and T6SS) and negatively regulates hemolysin EthA, which has been demonstrated to be essential for the invasion processes in fish. In order to develop a live attenuated vaccine (LAV) with high invasiveness to be practically and economically used as immersion-administered vaccine in aquaculture, here, we generated a random mutation library of esrB sequences by error-prone PCR and introduced them into the E. tarda esrB deletion mutant. The mutant YWZ47 with significantly increased hemolytic activity and low T3SS and T6SS secretion was screened. Phenotypes including extracellular protein profiles, invasion in macrophages, lethality toward fish, and infection kinetics were investigated in the wild-type strain EIB202 and the mutants Delta esrB, Delta T3SS, Delta T6SS, Delta T3SS/Delta T6SS, and YWZ47. Compared to the documented LAV strain Delta esrB, YWZ47 showed higher invasive capability and low in vivo virulence toward fish. Significantly higher relative percent survival (RPS) could be generated in turbot (Scophthalmus maximus) against the challenge of the wild-type EIB202 when inoculated through immersion route, and the RPS was comparable with that of Delta esrB through intraperitoneal (i.p.) injection inoculation. Two mutated points, K167M and H197L, were found by sequence analysis of EsrB(YWZ47) variant. These structural modifications underpin the variations in the regulatory functions of the mutant and wild-type EsrB. This study promoted understanding of virulence regulation by EsrB in E. tarda and presented a promising candidate of invasive attenuated vaccine used in aquaculture industries.