Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin, 300387, China.
Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin, 300387, China.
Dev Comp Immunol. 2022 Dec;137:104520. doi: 10.1016/j.dci.2022.104520. Epub 2022 Aug 27.
Complement plays an important role in the innate immune system, and it comprises about 35 individual proteins. In mammals, complement is activated via three different pathways, the classical pathway, the alternative pathway, and the lectin pathway. All three activation pathways produce C3-convertase in different forms. C3-convertase cleaves C3 to C3a and C3b and initiates a cascade of cleavage and activation, eventually resulting in the formation of the membrane attack complex. Complement activation results in the generation of activated fragments that are involved in microbial killing, phagocytosis, inflammatory reactions, immune complex clearance, and antibody production. Although the complement system has been studied extensively in mammals, complement is less well understood in teleosts. This review summarizes the current knowledge of the teleost complement components involved in phagocytosis, chemotaxis, and cell lysis. We report the characterized complement components in various teleost species. In addition, we provide a comprehensive compilation of complement regulators, and this information is used to analyze the role of complement regulators in pathogen infection. The influence of complement receptors on the immune responses of teleosts is reviewed. Finally, we propose directions for future study of the molecular evolution, structure, and function of complement components in teleosts. This review provides new insights into the complement system of recognition and defense, and such knowledge is essential for the development of new immune strategies in aquaculture.
补体在先天免疫系统中起着重要作用，它由大约 35 种不同的蛋白质组成。在哺乳动物中，补体通过三种不同的途径激活，即经典途径、替代途径和凝集素途径。这三种激活途径以不同的形式产生 C3 转化酶。C3 转化酶将 C3 切割成 C3a 和 C3b，并启动一系列的切割和激活反应，最终导致膜攻击复合物的形成。补体激活导致生成的活性片段参与微生物杀伤、吞噬、炎症反应、免疫复合物清除和抗体产生。尽管补体系统在哺乳动物中已经得到了广泛的研究，但在硬骨鱼中，补体的了解还比较少。这篇综述总结了硬骨鱼补体成分在吞噬、趋化和细胞裂解中的作用。我们报告了各种硬骨鱼物种中已鉴定的补体成分。此外，我们还提供了补体调节剂的综合汇编，并利用这些信息来分析补体调节剂在病原体感染中的作用。补体受体对硬骨鱼免疫反应的影响也进行了综述。最后，我们提出了硬骨鱼补体成分的分子进化、结构和功能的未来研究方向。这篇综述为补体的识别和防御系统提供了新的见解，这种知识对于水产养殖中新型免疫策略的发展至关重要。
