Cloning and Characterization of Surface-Localized α-Enolase of Streptococcus iniae, an Effective Protective Antigen in Mice

International Journal of Molecular Sciences

Jun Wang¹  Kaiyu Wang¹  Defang Chen²  Yi Geng¹  Xiaoli Huang²  Yang He¹  Lili Ji¹  Tao Liu¹  Erlong Wang¹  Qian Yang¹  Weimin Lai¹ 

[1] Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China; E-Mails:;Department of Aquaculture, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China; E-Mails:

关键词: Streptococcus iniae;    α-enolase;    characterization;    functions;    surface location;    protective antigen;    mice;   

DOI  :  10.3390/ijms160714490

来源: mdpi

【 摘 要 】

Streptococcus iniae is a major fish pathogen that can also cause human bacteremia, cellulitis and meningitis. Screening for and identification of protective antigens plays an important role in developing therapies against S. iniae infections. In this study, we indicated that the α-enolase of S. iniae was not only distributed in the cytoplasm and associated to cell walls, but was also secreted to the bacterial cell surface. The functional identity of the purified recombinant α-enolase protein was verified by its ability to catalyze the conversion of 2-phosphoglycerate (2-PGE) to phosphoenolpyruvate (PEP), and both the recombinant and native proteins interacted with human plasminogen. The rabbit anti-rENO serum blockade assay shows that α-enolase participates in S. iniae adhesion to and invasion of BHK-21 cells. In addition, the recombinant α-enolase can confer effective protection against S. iniae infection in mice, which suggests that α-enolase has potential as a vaccine candidate in mammals. We conclude that S. iniae α-enolase is a moonlighting protein that also associates with the bacterial outer surface and functions as a protective antigen in mice.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.