Construction of Salmonella Pullorum ghost by co-expression of lysis gene E and the antimicrobial peptide SMAP29 and evaluation of its immune efficacy in specific-pathogen-free chicks  

作　　者：TIAN Qiu-feng ZHOU Wei SI Wei YI Fei HUA Xin YUE Min CHEN Li-ping LIU Si-guo YU Shen-ye 

机构地区：[1]Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, P.R. China [2]Heilongjiang Bayi Agricultural University, Daqing 163319, P.R. China [3]College of Animal Sciences, Zhejiang University, Hangzhou 310058, P.R. China

出　　处：《Journal of Integrative Agriculture》2018年第1期197-209,共13页农业科学学报（英文版）

基　　金：supported by grants from the National Key Research and Development Program of China (2016YFD0501608);the National Natural Science Foundation of China (31470893);the Special Fund for Agro-scientific Research in the Public Interest,China (201403054);the National High Technology Research and Development Program of China (2011AA10A210)

摘　　要：In this study, a safety enhanced Salmonella Pullorum （S. Pullorum） ghost was constructed using an antimicrobial peptide gene, and evaluated for its potential as a Pullorum disease （PD） vaccine candidate. The antimicrobial peptide SMAP29 was co-expressed with lysis gene E to generate S. Pullorum ghosts. No viable bacteria were detectable either in the fermentation culture after induction of gene E- and SMAP29-mediated lysis for 24 h or in the lyophilized ghost products. Specific-pathogen- free （SPF） chicks were intraperitoneally immunized with ghosts at day 7 of age and no mortality, clinical symptoms or signs of PD such as anorexia, depression and diarrhea were observed. On challenge with a virulent S. Pullorum strain at 4 wk post-immunization, a comparatively higher level of protection was observed in the S. Pullorum ghost immunized chickens with a minimum of pathological lesions and bacterial loads compared to the birds in inactivated vaccine groups. In addition, immunization with the S. Pullorum ghosts induced a potent systemic IgG response and was associated with significantly increased levels of cytokine IFN-y and IL-4 and relative percentages of CD4＋ and CD8＋ T lymphocytes. Our results indicate that SMAP29 can be employed as a new secondary lethal protein to enhance the safety of bacterial ghosts, and to prepare a non-living bacterial vaccine candidate that can prevent PD in chickens.In this study, a safety enhanced Salmonella Pullorum （S. Pullorum） ghost was constructed using an antimicrobial peptide gene, and evaluated for its potential as a Pullorum disease （PD） vaccine candidate. The antimicrobial peptide SMAP29 was co-expressed with lysis gene E to generate S. Pullorum ghosts. No viable bacteria were detectable either in the fermentation culture after induction of gene E- and SMAP29-mediated lysis for 24 h or in the lyophilized ghost products. Specific-pathogen- free （SPF） chicks were intraperitoneally immunized with ghosts at day 7 of age and no mortality, clinical symptoms or signs of PD such as anorexia, depression and diarrhea were observed. On challenge with a virulent S. Pullorum strain at 4 wk post-immunization, a comparatively higher level of protection was observed in the S. Pullorum ghost immunized chickens with a minimum of pathological lesions and bacterial loads compared to the birds in inactivated vaccine groups. In addition, immunization with the S. Pullorum ghosts induced a potent systemic IgG response and was associated with significantly increased levels of cytokine IFN-y and IL-4 and relative percentages of CD4＋ and CD8＋ T lymphocytes. Our results indicate that SMAP29 can be employed as a new secondary lethal protein to enhance the safety of bacterial ghosts, and to prepare a non-living bacterial vaccine candidate that can prevent PD in chickens.

关 键 词：Salmonella Pullorum bacterial ghost antimicrobial peptide immune response immune protection 

分 类 号：S0[农业科学]