Wang Lei, Zhang Fumiao, Chen Yadong, Wang Shuangyan, Chen Zhangfan, Zhou Qian, Chen Songlin
Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Qingdao, 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Shandong Normal University, Jinan, 250014, China.
Fish Shellfish Immunol. 2022 Apr;123:113-126. doi: 10.1016/j.fsi.2022.02.051. Epub 2022 Feb 24.
IgT is a specific Ig isotype in teleosts, which plays extremely important roles in the mucosal immunity of fish. In the present study, the membrane-bound and secretory IgT of the half-smooth tongue sole (Cynoglossus semilaevis) were identified for the first time. The V-D-J-C structure of two forms of csIgT are translated by the same Cτ gene, and the secretory tail and transmembrane domain were encoded through alternative splicing at the 3' end of the Cτ4. The CH regions of csIgT had high similarity with that of other flatfish (P. olivaceus and S. maximus). In healthy C. semilaevis, sIgT and mIgT were mainly expressed in mucus related tissues such as skin, intestine and gill. The transcript levels of sIgT and mIgT mRNA showed a significant induction in the immune-related tissues upon Vibrio Harveyi infection. A polyclonal rabbit anti-csIgT was successfully prepared using the csIgT heavy chain recombinant protein. Using this antibody, we detected the native IgT with the molecular mass at 220 kDa in skin total protein under non-reducing SDS-PAGE condition. Immunofluorescence analysis indicated that IgT B lymphocytes were intensively located in the skin, gill, intestine, and head kidney of C. semilaevis. These results suggest that IgT may participate in the immune response of C. semilaevis, which will facilitate the investigations of the immunoglobulins of marine fish.
IgT是硬骨鱼中的一种特异性免疫球蛋白同种型，在鱼类的黏膜免疫中发挥着极其重要的作用。在本研究中，首次鉴定了半滑舌鳎（Cynoglossus semilaevis）的膜结合型和分泌型IgT。两种形式的csIgT的V-D-J-C结构由同一个Cτ基因翻译而来，分泌尾和跨膜结构域通过Cτ4 3'端的可变剪接进行编码。csIgT的CH区域与其他比目鱼（P. olivaceus和S. maximus）的CH区域具有高度相似性。在健康的半滑舌鳎中，sIgT和mIgT主要在皮肤、肠道和鳃等与黏液相关的组织中表达。感染哈维氏弧菌后，免疫相关组织中sIgT和mIgT mRNA的转录水平显著上调。利用csIgT重链重组蛋白成功制备了兔抗csIgT多克隆抗体。使用该抗体，我们在非还原SDS-PAGE条件下检测到皮肤总蛋白中分子量为220 kDa的天然IgT。免疫荧光分析表明，IgT B淋巴细胞密集分布在半滑舌鳎的皮肤、鳃、肠道和头肾中。这些结果表明，IgT可能参与半滑舌鳎的免疫反应，这将有助于对海洋鱼类免疫球蛋白的研究。
