Structural characteristics and mucosal immune response of the interbranchial lymphoid tissue in the gills of flounder (Paralichthys olivaceus)
Structural characteristics and mucosal immune response of the interbranchial lymphoid tissue in the gills of flounder (Paralichthys olivaceus)
复制标题
牙鲆鳃内鳃间淋巴组织的结构特征和粘膜免疫反应
DOI：
10.1016/j.fsi.2022.03.022
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发表时间：
2022-03-22
影响因子：
4.7
通讯作者：
Zhan, Wenbin
中科院分区：
文献类型：
--
作者：
Liang, Chengcheng;Sheng, Xiuzhen;Zhan, Wenbin
鳃间淋巴组织（ILT）是近年来在鱼类中发现的一种特殊的淋巴上皮组织。然而，ILT的结构变异和粘膜免疫功能在很大程度上仍然未知。本研究首次发现抗Zap-70单克隆抗体B能特异性识别牙鲆外周血白细胞中的ZAP-70蛋白和CD 4 -1（+）、CD 4 -2（+）和CD 813（+）T细胞，而不能识别IgM（+）B细胞。在横切面上，我们发现Zap-70（+）细胞聚集在鳃间裂底部的上皮细胞中，并沿着鳃丝的传入和传出边缘分布，在这些上皮细胞中可见一个含有弥散淋巴样细胞的上皮细胞网，证实这些结构为ILT;在矢状位视图中，Zap-70+细胞位于细丝的基部（这里称为近端ILT，pILT）和层间上皮（称为远端ILT，dILT）中。此外，在这些部位还分布有少量IgM（+）B细胞。pILT和dILT的淋巴上皮在变态前和顶极后的仔鱼中非常薄，Zap-70（+）细胞数量很少，在幼鱼和成体中逐渐增厚，Zap-70（+）细胞数量较多。在ILT中鉴定了CD 4 -1（+）/Zap-70（+）、CD 4 -2（+）/Zap-70（+）和CD 813（+）/Zap-70（+）T细胞亚群的聚集体。灭活迟缓爱德华氏菌浴苗后腹腔注射EdU，3d和7 d EdU+和Zap-70+细胞数量明显增加，EdU+/Zap-70+细胞共定位表明存在增殖性T细胞，同时表达MHC Ⅱ类分子的细胞增多。这些结果表明，比目鱼鳃的ILT是诱导局部T细胞介导免疫的重要部位，这将有助于更好地理解硬骨鱼的粘膜免疫和防御机制。
A specialized lymphoepithelial tissue termed the interbranchial lymphoid tissue (ILT) is recently identified in several fish species. However, the structural variation and mucosal immune functions of the ILT remain largely unknown. In this study, the anti-Zap-70 MAb was firstly determined to specifically recognize ZAP-70 protein, and CD4-1(+), CD4-2(+) and CD813(+) T-cells, but not IgM(+) B cells, in peripheral blood leucocytes of flounder (Paralichthys olivaceus). Then we found that aggregates of Zap-70(+) cells were located in the epithelium covering the bottom of the interbranchial cleft and along the afferent and efferent edges of the filaments in a cross view, where a meshwork of epithelial cells containing diffused lymphoid cells was exhibited, confirming these structures as the ILT; In a sagittal view, Zap-70+ cells were situated at the base of the filaments (here named as proximal ILT, pILT) and in the interlamellar epithelium (named as distal ILT, dILT). Also, a few IgM(+) B cells were distributed at these sites. The lymphoepithelium within pILT and dILT was very thin with a low number of Zap-70(+) cells in pre metamorphosis and postclimax larvae of flounder, and got thicker containing much more Zap-70+ cells in juvenile and adult individuals. The aggregates of CD4-1(+)/Zap-70(+), CD4-2(+)/Zap-70(+), and CD813(+)/Zap-70(+) T-cell subsets were identified in the ILT. Post bath vaccination with inactivated Edwardsiella tarda and then intraperitoneal injection of EdU, the amounts of EdU+ and Zap-70(+) cells obviously increased at 3 d and 7 d, and co localization of EdU+/Zap-70+ cells identified the presence of proliferative T cells; meanwhile, MHC class II expressing cells were increased. These findings indicated that the ILT in gills of flounder was an important site for the induction of local T cell-mediated immunity, which would lead to a better understanding of mucosal immunity and defense mechanisms of teleost fish.