title: Characterization of Brucella abortus mutant strain Δ22915, a potential vaccine candidate.
abstract: Brucellosis, caused by Brucella spp., is an important zoonosis worldwide. Vaccination is an effective strategy for protection against Brucella infection in livestock in developing countries and in wildlife in developed countries. However, current vaccine strains including S19 and RB51 are pathogenic to humans and pregnant animals, limiting their use. In this study, we constructed the Brucella abortus (B. abortus) S2308 mutant strain Δ22915, in which the putative lytic transglycosylase gene BAB_RS22915 was deleted. The biological properties of mutant strain Δ22915 were characterized and protection of mice against virulent S2308 challenge was evaluated. The mutant strain Δ22915 showed reduced survival within RAW264.7 cells and survival in vivo in mice. In addition, the mutant strain Δ22915 failed to escape fusion with lysosomes within host cells, and caused no observable pathological damage. RNA-seq analysis indicated that four genes associated with amino acid/nucleotide transport and metabolism were significantly upregulated in mutant strain Δ22915. Furthermore, inoculation of ∆22915 at 105colony forming units induced effective host immune responses and long-term protection of BALB/c mice. Therefore, mutant strain ∆22915 could be used as a novel vaccine candidate in the future to protect animals against B. abortus infection.
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Bao
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China.
authors.forename: Mingxing
authors.initials: M
authors.lastname: Tian
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China.
authors.forename: Jiameng
authors.initials: J
authors.lastname: Liu
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China.
authors.forename: Chan
authors.initials: C
authors.lastname: Ding
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China. yus@shvri.ac.cn.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China. yus@shvri.ac.cn.
authors.forename: Shengqing
authors.initials: S
authors.lastname: Yu
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000276:immunology; D002004:Brucella Vaccine / Q000276:immunology* / Q000627:therapeutic use; D002003:Brucella abortus / Q000235:genetics* / Q000276:immunology; D002007:Brucellosis, Bovine / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D002417:Cattle; D005260:Female; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D051379:Mice; D008807:Mice, Inbred BALB C; D000067996:RAW 264.7 Cells; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D059467:Transcriptome / Q000235:genetics
chemical_list: D002004:Brucella Vaccine