College of Fishery, Guangdong Ocean University, Zhanjiang, 524088, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524088, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524088, China.
College of Fishery, Guangdong Ocean University, Zhanjiang, 524088, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524088, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang 524088, China.
Fish Shellfish Immunol. 2018 Jan;72:95-103. doi: 10.1016/j.fsi.2017.10.008. Epub 2017 Oct 24.
Interaction of CD28 with CD80 or CD86 molecules provides a costimulatory signals required in T cell activation. In this study, we cloned and analyzed a CD28 gene (On-CD28) and a CD80/86 gene (On-CD80/86) from Nile tilapia (Oreochromis niloticus). Sequence analysis revealed the typical characteristics of On-CD28 protein; for instance, the proline-based motif (TYPPPL) is essential in binding of CD28 to CD80/86 ligands. Moreover, an extracellular Ig domain was found in On-CD80/86; this domain is responsible in binding of CD28 to CD80/86 receptors. Subcellular localization analysis showed that both On-CD28 and On-CD80/86 were distributed predominantly in the cytomembrane. Yeast two-hybrid assay showed that On-CD28 directly interacted with On-CD80/86. On-CD28 and On-CD80/86 transcripts were detected in all the examined tissues of healthy Nile tilapia, and the highest expression levels of On-CD28 and On-CD80/86 were detected in the brain and heart, respectively. Following a bacterial challenge using Streptococcus agalactiae in vivo, On-CD28 and On-CD80/86 were upregulated in head kidney, spleen, intestines, and brain. However, they showed different expression profiles in response to stimulation with inactivated S. agalactiae in vitro. These findings indicated that the interaction of On-CD28 with On-CD80/86 provides a costimulatory signals that possibly play an important role in T cell activation during S. agalactiae infection.
CD28 与 CD80 或 CD86 分子的相互作用提供了 T 细胞激活所需的共刺激信号。在这项研究中，我们从尼罗罗非鱼（Oreochromis niloticus）中克隆和分析了一个 CD28 基因（On-CD28）和一个 CD80/86 基因（On-CD80/86）。序列分析显示 On-CD28 蛋白具有典型特征；例如，脯氨酸基模（TYPPPL）是 CD28 与 CD80/86 配体结合所必需的。此外，在 On-CD80/86 中发现了一个细胞外 Ig 结构域；该结构域负责 CD28 与 CD80/86 受体的结合。亚细胞定位分析表明，On-CD28 和 On-CD80/86 主要分布在细胞质膜上。酵母双杂交试验表明，On-CD28 与 On-CD80/86 直接相互作用。在健康尼罗罗非鱼的所有检测组织中均检测到 On-CD28 和 On-CD80/86 的转录本，On-CD28 和 On-CD80/86 的表达水平最高分别在脑中，心脏中。体内用无乳链球菌（Streptococcus agalactiae）攻毒后，头肾、脾脏、肠和脑中的 On-CD28 和 On-CD80/86 上调。但是，它们在体外用灭活的 S.agalactiae 刺激时表现出不同的表达谱。这些发现表明，On-CD28 与 On-CD80/86 的相互作用提供了共刺激信号，可能在链球菌感染期间 T 细胞激活中发挥重要作用。
