title: Characterization of the immunogenicity and pathogenicity of malate dehydrogenase in Brucella abortus.
abstract: Brucella abortus is a gram-negative, facultative intracellular pathogen that causes brucellosis, a chronic zoonotic disease resulting in abortion in pregnant cattle and undulant fever in humans. Malate dehydrogenase (MDH), a key enzyme in the tricarboxylic acid cycle, plays important metabolic roles in aerobic energy producing pathways and in malate shuttle. In this study, the MDH-encoding gene for malate dehydrogenase mdh of B. abortus S2308 was cloned, sequenced and expressed. Western blot analysis demonstrated that MDH is an immunogenic membrane-associated protein. In addition, recombinant MDH showed sero-reactivity with 30 individual bovine B. abortus-positive sera by enzyme-linked immunosorbent assay, indicates that MDH may be used as a candidate marker for sero-diagnosis of brucellosis. Furthermore, MDH exhibits fibronectin and plasminogen-binding ability in immunoblotting assay. Inhibition assays on HeLa cells demonstrated that rabbit anti-serum against MDH significantly reduced both bacterial adherence and invasion abilities (p < 0.05), suggesting that MDH play a role in B. abortus colonization. Our results indicated that MDH is not only an immunogenic protein, but is also related to bacterial pathogenesis and may act as a new virulent factor, which will benefit for further understanding the MDH's roles in B. abortus metabolism, pathogenesis and immunity.
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 518 Ziyue Road, Shanghai, 200241, People's Republic of China.
authors.forename: Xiangan
authors.initials: X
authors.lastname: Han
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Tong
authors.forename: Mingxing
authors.initials: M
authors.lastname: Tian
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Sun
authors.forename: Shaohui
authors.initials: S
authors.lastname: Wang
authors.forename: Chan
authors.initials: C
authors.lastname: Ding
authors.forename: Shengqing
authors.initials: S
authors.lastname: Yu
mesh_terms: D015153:Blotting, Western; D002003:Brucella abortus / Q000201:enzymology* / Q000472:pathogenicity*; D002006:Brucellosis / Q000276:immunology / Q000382:microbiology; D002952:Citric Acid Cycle / Q000235:genetics / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D006367:HeLa Cells; D006801:Humans; D008291:Malate Dehydrogenase / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*
chemical_list: D008291:Malate Dehydrogenase