Frontiers in Microbiology (Oct 2015)

Immunization with Individual Proteins of the Lrp/AsnC Family Induces Protection Against Brucella melitensis 16M Challenges in Mice

  • Xinhui eWang,
  • Xinhui eWang,
  • Xinhui eWang,
  • Chang eAn,
  • Chang eAn,
  • Mingjuan eYang,
  • Xinran eLi,
  • Xinran eLi,
  • Yuehua eKe,
  • Shuangshuang eLei,
  • Xiaoyang eXu,
  • Jiuxuan eYu,
  • Hang eRen,
  • xinying eDu,
  • zhoujia ewang,
  • Yefeng eQiu,
  • Bo eLiu,
  • Zeliang eChen

DOI
https://doi.org/10.3389/fmicb.2015.01193
Journal volume & issue
Vol. 6

Abstract

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Brucellosis is one of the most common zoonoses worldwide. Subunit vaccines are promising for the prevention of human brucellosis. In our previous protective antigen screening studies, we identified a new protective antigen, BMEI0357, which belongs to the Lrp/asnC protein family, a conserved transcriptional regulator in bacteria that is absent in eukaryotes. In the present study, the Brucella genome annotation was screened and a total of 6 proteins were identified as members of the Lrp/AsnC family. Lrp/AsnC proteins have 2 domains that are conserved among the family members. However, sequence similarities between these proteins ranged from 9% to 50%, indicating high sequence heterogeneity. To test whether proteins of this family have similar characteristics, all 6 proteins were cloned and expressed in Escherichia coli. The recombinant proteins were purified and their protective efficacy was evaluated in BALB/c mice challenged with Brucella melitensis 16M. The results show that all 6 Lrp/AsnC proteins could induce a protective immune response against Brucella melitensis 16M. Antibodies against the Lrp/AsnC proteins were detected in the immunized mice. However, levels of antibodies against these proteins were relatively variable in human brucellosis sera. Taken together, our results show that these 6 proteins of the Lrp/AsnC family in Brucella could induce protective immune responses in mice.

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