文献类型：期刊文献

英文题名：Construction of a Streptococcus agalactiae phoB mutant and evaluation of its potential as an attenuated modified live vaccine in golden pompano, Trachinotus ovatus

作者：Cai, Xiaohui[1];Wang, Bei[1];Peng, Yinhui[2];Li, Yuan[1];Lu, Yishan[1];Huang, Yucong[1];Jian, Jichang[1];Wu, Zaohe[1]

机构：[1]Guangdong Ocean Univ, Coll Fishery, Guangdong Prov Key Lab Pathogen Biol & Epidemiol, Key Lab Control Dis Aquat Anim Guangdong Higher E, Zhanjiang 524025, Peoples R China;[2]Guangxi Inst Oceanol, Guangxi Key Lab Marine Biotechnol, Beihai 536000, Peoples R China

年份：2017

卷号：63

起止页码：405

外文期刊名：FISH & SHELLFISH IMMUNOLOGY

收录：SCI-EXPANDED(收录号：WOS:000398870700044)、、WOS

基金：The authors wish to thank all the laboratory members' suggestion on this manuscript. This work was supported by Graduate education innovation program of Guangdong Ocean University (201603), National "Twelfth Five -Year" for Science & Technology Support of China (Grant No. 2012BAD17B03), National Natural Science Foundation of China (Grant No. 31302226), Science & Technology Planning Project of Guangdong Province of China (Grant No. 2012B020308009), Natural Science Foundation of Guangxi Province of China (Grant No. 2012GXNSFAA053065, 1222013-2, GXIF-2012-02) and National Public Welfare Project (Grant No. 201205028-4).

语种：英文

外文关键词：Streptococcus agalactiae; phoB; Live attenuated vaccine; Golden pompan

外文摘要：Streptococcus agalactiae is a Gram-positive pathogen that can survive inside professional phagocytes and nonphagocytic cells to cause septicemia and meningoencephalitis in freshwater and marine fish. However, vaccines based on extracellular products (ECP) and formalin-killed whole S. agalactiae cells, as well as subunit vaccine are unable to protect fish from infection by variant serotypes S. agalactiae. The search for live attenuated vaccine with highly conserved and virulent-related genes is essential for producing a vaccine to help understand and control streptococcosis In this study, the phoB gene was cloned from pathogenic S. agalactiae TOS01 strain and the mutant strain SA Delta phoB was constructed via allelic exchange mutagenesis. The results showed that the deduced amino acid of S. agalactiae TOS01 shares high similarities with other Streptococcus spp. and has high conserved response regulator receiver domain (REC) and DNA-binding effector domain of two-component system response regulators (Trans_reg_C). Cell adherence and invasion assays, challenge experiments and histopathological changes post vaccination were performed and observed, the results showed that the mutant strain SA Delta phoB has a lower adherence and invasion rate and less virulent than the wild type strain in golden pompano, and it doesn't induce clinical symptoms and obvious pathological changes in golden pompano, thereby indicating that the deletion of phoB affects the virulence and infectious capacity of S. agalactiae. Golden pompano vaccinated via intraperitoneal injection SA Delta phoB had the relative percent survival value of 93.1% after challenge with TOS01, demonstrating its high potential as an effective attenuated live vaccine candidate. Real-time PCR assays showed that the SA Delta phoB was able to enhance the expression of immune-related genes, including MHC-I, MyD88, IL-22 and IL-10 after vaccination, indicating that the SA Delta phoB is able to induce humoral and cell-mediated immune response in golden pompano over a long period of time. (C) 2016 Published by Elsevier Ltd.