title: Inactivation of the ABC transporter ATPase gene in Brucella abortus strain 2308 attenuated the virulence of the bacteria.
abstract: Brucella abortus is a Gram-negative, facultative intracellular bacterial pathogen of human and other animals. Brucella lipopolysaccharide has been identified as an important virulence factor. In this study, the ABC transporter ATPase gene (BAB1_0542) of B. abortus strain S2308 was inactivated by deleting a 446-bp fragment from the gene, thereby generating the mutant strain, S2308ΔATP. Real time PCR analysis confirmed the inactivation of this gene with no polar effect on the transcription of adjacent genes on the chromosome. The mutant was identified as a rough phenotype strain using heat agglutination test and crystal violet staining. The mutant strain had a different growth rate in Tryptic Soy Broth (TSB), compared to the wild type S2308 strain. Moreover, the mutant strain showed attenuated virulence in vitro and in vivo in RAW264.7 macrophages and Balb/c mice, respectively. Complementation of the mutant strain recovered the smooth phenotype of the bacteria and the complemented strain C2308ΔATP survived for more than four weeks in Balb/c mice, comparable to wild type strain S2308. Furthermore, immunization with the mutant strain protected mice from virulent strain challenge, which suggests the potential for the mutant strain S2308ΔATP as a future vaccine candidate. MHC I, MHC II and co-stimulatory molecule expression levels in mice following infection of S2308ΔATP and S2308 were also investigated.
authors.affiliation: College of Veterinary Medicine, Yangzhou University, 48 Wenhuidong Road, Yangzhou 225009, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Xiangan
authors.initials: X
authors.lastname: Han
authors.forename: Haiwen
authors.initials: H
authors.lastname: Liu
authors.forename: Mingxing
authors.initials: M
authors.lastname: Tian
authors.forename: Chan
authors.initials: C
authors.lastname: Ding
authors.forename: Jun
authors.initials: J
authors.lastname: Song
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Sun
authors.forename: Zongping
authors.initials: Z
authors.lastname: Liu
authors.forename: Shengqing
authors.initials: S
authors.lastname: Yu
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology; D002003:Brucella abortus / Q000235:genetics* / Q000472:pathogenicity*; D002006:Brucellosis / Q000517:prevention & control; D002460:Cell Line; D005260:Female; D005786:Gene Expression Regulation; D020868:Gene Silencing; D005816:Genetic Complementation Test; D007114:Immunization / Q000592:standards; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D011897:Random Allocation; D017384:Sequence Deletion / Q000235:genetics; D014774:Virulence / Q000235:genetics*
chemical_list: D001428:Bacterial Vaccines; D000251:Adenosine Triphosphatases