Luo Junliang, Chen Yanghui, Huang Yongxiong, Feng Jiamin, Yuan Yunhao, Jian Jichang, Cai Shuanghu, Yang Shiping
Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture & Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, China.
Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture & Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, China.
Fish Shellfish Immunol. 2023 Apr;135:108621. doi: 10.1016/j.fsi.2023.108621. Epub 2023 Feb 17.
C-type lectins (CTLs), as a member of pattern recognition receptors, play a vital role in the innate immune response of invertebrates to eliminate micro-invaders. In this study, a novel CTL of Litopenaeus vannamei, namely, LvCTL7, was successfully cloned, with an open reading frame of 501 bp and a capability to encode 166 amino acids. Blast analysis showed that the amino acid sequence similarity between LvCTL7 and MjCTL7 (Marsupenaeus japonicus) was 57.14%. LvCTL7 was mainly expressed in hepatopancreas, muscle, gill and eyestalk. Vibrio harveyi can significantly affect LvCTL7 expression level in hepatopancreases, gills, intestines and muscles (p < 0.05). LvCTL7 recombinant protein can bind to Gram-positive bacteria (Bacillus subtilis) and Gram-negative bacteria (Vibrio parahaemolyticus and V. harveyi). It can cause the agglutination of V. alginolyticus and V. harveyi, but it had no effect on Streptococcus agalactiae and B. subtilis. The expression levels of SOD, CAT, HSP 70, Toll 2, IMD and ALF genes in the challenge group added with LvCTL7 protein were more stable than those in the direct challenge group (p < 0.05). Moreover, knockdown of LvCTL7 by double-stranded RNA interference downregulated the expression levels of genes (ALF, IMD and LvCTL5) that protect against bacterial infection (p < 0.05). These results indicated that LvCTL7 had microbial agglutination and immunoregulatory activity, and it was involved in the innate immune response against Vibrio infection in L. vannamei.
C型凝集素（CTLs）作为模式识别受体的一员，在无脊椎动物的天然免疫反应中发挥着至关重要的作用，以清除微小入侵者。在本研究中，凡纳滨对虾一种新的CTL，即LvCTL7，被成功克隆，其开放阅读框为501 bp，能够编码166个氨基酸。Blast分析表明，LvCTL7与日本囊对虾MjCTL7的氨基酸序列相似性为57.14%。LvCTL7主要在肝胰腺、肌肉、鳃和眼柄中表达。哈维氏弧菌可显著影响肝胰腺、鳃、肠和肌肉中LvCTL7的表达水平（p < 0.05）。LvCTL7重组蛋白可与革兰氏阳性菌（枯草芽孢杆菌）和革兰氏阴性菌（副溶血性弧菌和哈维氏弧菌）结合。它可导致溶藻弧菌和哈维氏弧菌凝集，但对无乳链球菌和枯草芽孢杆菌无作用。添加LvCTL7蛋白的攻击组中SOD、CAT、HSP 70、Toll 2、IMD和ALF基因的表达水平比直接攻击组更稳定（p < 0.05）。此外，通过双链RNA干扰敲低LvCTL7可下调抗细菌感染相关基因（ALF、IMD和LvCTL5）的表达水平（p < 0.05）。这些结果表明，LvCTL7具有微生物凝集和免疫调节活性，且参与凡纳滨对虾抗弧菌感染的天然免疫反应。
