title: GapA, a potential vaccine candidate antigen against Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus).
abstract: Streptococcosis due to the bacterium Streptococcus agalactiae (S. agalactiae) has resulted in enormous economic losses in aquaculture worldwide, especially in the tilapia culture industry. Previously, there were limited vaccines that could be employed against streptococcosis in tilapia. This study aimed to develop a vaccine candidate using the glyceraldehyde-phosphate dehydrogenase protein (GapA) of S. agalactiae encoded by the gapA gene. Tilapia were intraperitoneally injected with PBS, PBS + Freund's adjuvant, PBS + Montanide's adjuvant, GapA + Freund's adjuvant, GapA + Montanide's adjuvant, killed S. agalactiae whole cells (WC)+Freund's adjuvant, or killed S. agalactiae whole cells (WC)+ Montanide's adjuvant. They were then challenged with S. agalactiae, and the relative percentage survival (RPS) was monitored 14 days after the challenge. The highest RPSs were observed in the WC groups, with 76.7% in WC + Freund's adjuvant and 74.4% in WC + Montanide's adjuvant groups; these were followed by the GapA groups, with 63.3% in GapA + Freund's adjuvant and 45.6% in GapA + Montanide's adjuvant groups. The RPS of the PBS group was 0%, and those of PBS + Freund's adjuvant and PBS + Montanide's adjuvant groups were 6.7% and 3.3%, respectively. Additionally, the IgM antibody responses elicited in GapA groups and WC groups were significantly higher than those in PBS groups. Furthermore, the expressions of cytokine (IL-1β and TNF-α) mRNAs in the GapA groups and WC groups were significantly higher than those in the PBS groups. Taken together, these results reveal that the GapA protein is a promising vaccine candidate that could be used to prevent streptococcosis in tilapia.
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; School of Life Sciences, Beijing Normal University, Beijing, 100875, China; National Institute of Biological Sciences, Zhongguancun Life Science Park, Changping, 102206, Beijing, China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Angen
authors.initials: A
authors.lastname: Yu
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Lan
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Minqiang
authors.initials: M
authors.lastname: Hu
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
authors.forename: Jiewei
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, 510225, China. Electronic address: linli@mail.hzau.edu.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China. Electronic address: weishun@mail.hzau.edu.cn.
authors.forename: Shun
authors.initials: S
authors.lastname: Wei
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology*; D000818:Animals; D023681:Cichlids; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005393:Fish Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D007274:Injections, Intraperitoneal / Q000662:veterinary; D030781:Organisms, Genetically Modified / Q000235:genetics; D011897:Random Allocation; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D022541:Streptococcal Vaccines / Q000235:genetics / Q000276:immunology*; D013292:Streptococcus agalactiae / Q000276:immunology*; D022223:Vaccines, Subunit / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D018829:Adhesins, Bacterial; C117938:GapA cytadhesin; D022541:Streptococcal Vaccines; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic
keywords: GapA; Streptococcus agalactiae; Tilapia; Vaccine