title: Cloning and Characterization of Surface-Localized α-Enolase of Streptococcus iniae, an Effective Protective Antigen in Mice.
abstract: 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.
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. wangjunzl@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. wangjunzl@126.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. kywangsicau@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. kywangsicau@126.com.
authors.forename: Kaiyu
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Aquaculture, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. chendf_sicau@126.com.
authors.forename: Defang
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. gengyisicau@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. gengyisicau@126.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Geng
authors.affiliation: Department of Aquaculture, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. hxldyq@126.com.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. heyang@sicau.edu.cn.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. heyang@sicau.edu.cn.
authors.forename: Yang
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. jllsicau@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. jllsicau@126.com.
authors.forename: Lili
authors.initials: L
authors.lastname: Ji
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. ltsicau@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. ltsicau@126.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. welsicau@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. welsicau@126.com.
authors.forename: Erlong
authors.initials: E
authors.lastname: Wang
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. yangqiansicau@126.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. yangqiansicau@126.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Basic Veterinary, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. nwm_mm2004@163.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang District Huimin Road No. 211, Chengdu 611130, China. nwm_mm2004@163.com.
authors.forename: Weimin
authors.initials: W
authors.lastname: Lai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D005988:Glyceric Acids / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D010728:Phosphoenolpyruvate / Q000737:chemistry; D010751:Phosphopyruvate Hydratase / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D005988:Glyceric Acids; C008885:2-phosphoglycerate; D010728:Phosphoenolpyruvate; D010751:Phosphopyruvate Hydratase
keywords: Streptococcus iniae; characterization; functions; mice; protective antigen; surface location; α-enolase