Lai Guolong, Li Xinran, Liu Sichang, Zhao Luyang, Xie Mengtian, Huang Li, Zhang Wenxuan, Bao Wenbing, Lin Yan, Chen Xinhua, Ding Yang
State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
Fish Shellfish Immunol. 2025 Jul 24;166:110596. doi: 10.1016/j.fsi.2025.110596.
CD8 T cells are critical cytotoxic effectors involved in pathogen clearance, including defense against parasitic infections in aquaculture species. In this study, we developed a monoclonal antibody specifically targeting the CD8α chain, enabling the identification of CD8 T cells in large yellow croaker Larimichthys crocea and providing a valuable tool for studying cytotoxic T cell responses in teleosts. Croaker CD8 T cells were more abundant in mucosal than systemic lymphoid organs, suggesting their preferential localization to sites of pathogen entry. Using this tool, we investigated CD8 T cell responses to Cryptocaryon irritans infection. During acute infection, CD8 T cells significantly proliferated in the spleen, head kidney (HK), and gills, accompanied by upregulation of cytotoxic genes including granzyme a, granzyme b, and perforin 1. Notably, a previously unrecognized depletion of CD8 T cells was observed in the spleen and HK, despite the total numbers of lymphocytes remaining unchanged. Our findings demonstrate an indispensable role of CD8 T cells as cytotoxic effectors involved in the defense against parasitic infection, and suggest their potential as valuable immunological biomarkers for disease monitoring or as targets for vaccine-based interventions in aquaculture.
CD8 T细胞是参与病原体清除的关键细胞毒性效应器，包括抵御水产养殖物种中的寄生虫感染。在本研究中，我们开发了一种特异性靶向CD8α链的单克隆抗体，能够鉴定大黄鱼（Larimichthys crocea）中的CD8 T细胞，并为研究硬骨鱼中的细胞毒性T细胞反应提供了有价值的工具。大黄鱼的CD8 T细胞在黏膜淋巴器官中比在系统性淋巴器官中更为丰富，这表明它们优先定位于病原体进入的部位。利用这一工具，我们研究了CD8 T细胞对刺激隐核虫感染的反应。在急性感染期间，CD8 T细胞在脾脏、头肾（HK）和鳃中显著增殖，同时包括颗粒酶a、颗粒酶b和穿孔素1在内的细胞毒性基因上调。值得注意的是，尽管淋巴细胞总数保持不变，但在脾脏和头肾中观察到了以前未被认识到的CD8 T细胞耗竭现象。我们的研究结果证明了CD8 T细胞作为参与抵御寄生虫感染的细胞毒性效应器的不可或缺的作用，并表明它们作为疾病监测中有价值的免疫生物标志物或水产养殖中基于疫苗干预的靶点的潜力。
