title: Molecular characterization and expression of CD2 in Nile tilapia (Oreochromis niloticus) in response to Streptococcus agalactiae stimulus.
abstract: The cluster of differentiation 2 (CD2), functioning as a cell adhesion and costimulatory molecule, plays a crucial role in T-cell activation. In this paper, the CD2 gene of Nile tilapia, Oreochromis niloticus (designated as On-CD2) was cloned and its expression pattern under the stimulation of Streptococcus agalactiae was investigated. Sequence analysis showed On-CD2 protein consists of two extracellular Ig-like domains, a transmembrane region, and a long proline-rich cytoplasmic tail, which is a hallmark of CD2, and several important structural characteristics required for T-cell activation were detected in the deduced amino acid sequence of On-CD2. In healthy tilapia, the On-CD2 transcripts were mainly detected in the head kidney, spleen, blood and thymus. Moreover, there was a clear time-dependent expression pattern of On-CD2 after immunized by formalin-inactivated S. agalactiae and the expression reached the highest level at 12 h in the brain and head kidney, 48 h in the spleen, and 72 h in the thymus, respectively. This is the first report on the expression of CD2 induced by bacteria vaccination in teleosts. These findings indicated that On-CD2 may play an important role in the immune response to intracellular bacteria in Nile tilapia.
authors.affiliation: College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Gan
authors.affiliation: College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Wang
authors.affiliation: College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China.
authors.forename: Jufen
authors.initials: J
authors.lastname: Tang
authors.affiliation: College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China. Electronic address: fishdis@163.com.
authors.forename: Yishan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China.
authors.forename: JiChang
authors.initials: J
authors.lastname: Jian
authors.affiliation: Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China.
authors.forename: Zaohe
authors.initials: Z
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: pinnie@ihb.ac.cn.
authors.forename: Pin
authors.initials: P
authors.lastname: Nie
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018801:CD2 Antigens / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D023681:Cichlids; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D009928:Organ Specificity; D010802:Phylogeny; D016415:Sequence Alignment / Q000662:veterinary; D013290:Streptococcal Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D013292:Streptococcus agalactiae / Q000502:physiology
chemical_list: D018801:CD2 Antigens
keywords: CD2; Fluorescent quantitative real-time PCR; Oreochromis niloticus; RACE; Streptococcus agalactiae