title: Rough brucella strain RM57 is attenuated and confers protection against Brucella melitensis.
abstract: Brucella melitensis (B. melitensis) is a facultative intracellular pathogen, which is the main epidemic strain in China. To overcome disadvantages of traditional live attenuated vaccines, in this study a rough mutant RM57 was induced from a B. melitensis isolate M1981. In order to uncover the reason of changes in the LPS of RM57, the nucleotide sequences and transcription levels of all known genes related to LPS synthesis were detected. As LPS plays an important role in outer membrane integrity, the sensitivities of RM57 to SDS and polymyxin B were examined. The results showed that the expression level of LPS genes of RM57 was not significantly changed, and RM57 was sensitive to polymyxin B, compared to its parent strain. In further study, the virulence and protective efficacy of RM57 in mice and guinea pigs were determined, and our data indicated that RM57 was attenuated and had good protection effects, especially in guinea pigs model. Overall, these results demonstrated that the artificially induced rough mutant strain RM57 was an efficacious vaccine candidate against the challenge of virulent B. melitensis. Our data presented here provided additional insight into the mechanism of LPS synthesis of Brucella spp.
authors.affiliation: Department of Inspection Technology Research, China Institute of Veterinary Drug Control, Beijing 100081, China; College of Animal Science and Veterinary Medicine, Shandong Agriculture University, Taian, Shandong 270018, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Inspection Technology Research, China Institute of Veterinary Drug Control, Beijing 100081, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Peng
authors.affiliation: Department of Inspection Technology Research, China Institute of Veterinary Drug Control, Beijing 100081, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Inspection Technology Research, China Institute of Veterinary Drug Control, Beijing 100081, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Inspection Technology Research, China Institute of Veterinary Drug Control, Beijing 100081, China.
authors.forename: Liangquan
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Inspection Technology Research, China Institute of Veterinary Drug Control, Beijing 100081, China. Electronic address: dingjiabo@126.com.
authors.forename: Jiabo
authors.initials: J
authors.lastname: Ding
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D002004:Brucella Vaccine / Q000235:genetics* / Q000276:immunology*; D017347:Brucella melitensis / Q000235:genetics* / Q000276:immunology* / Q000472:pathogenicity; D002006:Brucellosis / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D002681:China; D004195:Disease Models, Animal; D005260:Female; D005798:Genes, Bacterial / Q000235:genetics; D006168:Guinea Pigs / Q000276:immunology; D007114:Immunization; D008070:Lipopolysaccharides / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D009154:Mutation / Q000235:genetics; D011112:Polymyxin B / Q000494:pharmacology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014613:Vaccines, Attenuated / Q000235:genetics* / Q000276:immunology*; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002004:Brucella Vaccine; D008070:Lipopolysaccharides; D012336:RNA, Ribosomal, 16S; D014613:Vaccines, Attenuated; D011112:Polymyxin B
keywords: Brucella; LPS; Rough strain; Vaccine candidate