College of Oceanography, Hohai University, Nanjing, China.
Postdoctoral Innovation Practice Base, Jiangsu Shuixian Industrial Company Limited, Yangzhou, China.
Front Immunol. 2020 Mar 12;11:436. doi: 10.3389/fimmu.2020.00436. eCollection 2020.
C-type lectins (CTLs) have received widespread attention in animal immune responses. In the present study, two CTLs ( and ) were identified from obscure puffer . The open reading frames of ToCTL1 and ToCTL2 were 687 and 1,380 bp, respectively. The predicted ToCTL1 and ToCTL2 proteins contained a single transmembrane region and one typical carbohydrate recognition domain (CRD). Quantitative real-time polymerase chain reaction detected and transcripts in all examined tissues, with high levels in the intestine and kidney, and their expression levels were remarkably altered upon and infection. The recombinant proteins ToCTL1-CRD and ToCTL2-CRD agglutinated the Gram-negative and Gram-positive bacteria in a Ca-dependent manner. rToCTL1-CRD and rToCTL2-CRD exhibited evident binding activities against seven kinds of bacteria and polysaccharides (lipopolysaccharide and peptidoglycan) in a Ca-independent manner. Moreover, rToCTL1-CRD and rToCTL2-CRD could inhibit the growth of four types of bacteria . These findings collectively demonstrated that ToCTL1 and ToCTL2 could be involved in host defense against bacterial infection in .
C 型凝集素（CTLs）在动物免疫反应中受到广泛关注。本研究从暗纹东方鲀中鉴定出两种 CTLs（ 和 ）。ToCTL1 和 ToCTL2 的开放阅读框分别为 687 和 1380bp，预测的 ToCTL1 和 ToCTL2 蛋白均含有一个单一的跨膜区域和一个典型的糖识别结构域（CRD）。定量实时聚合酶链反应检测到 和 在所有检测组织中均有转录本，在肠道和肾脏中表达水平较高，在 和 感染后其表达水平显著改变。重组蛋白 ToCTL1-CRD 和 ToCTL2-CRD 以 Ca 依赖性方式凝集革兰氏阴性菌和革兰氏阳性菌。rToCTL1-CRD 和 rToCTL2-CRD 以 Ca 非依赖性方式表现出对七种细菌和多糖（脂多糖和肽聚糖）的明显结合活性。此外，rToCTL1-CRD 和 rToCTL2-CRD 可以抑制四种类型的细菌的生长。这些发现共同表明，ToCTL1 和 ToCTL2 可能参与暗纹东方鲀抵抗细菌感染的宿主防御。
