Sun Jiejie, Wang Lingling, Song Linsheng
Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, 116023, China.
Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, 116023, China; Dalian Key Laboratory of Aquatic Animal Disease Control, Dalian Ocean University, Dalian, 116023, China.
Dev Comp Immunol. 2023 Feb;139:104565. doi: 10.1016/j.dci.2022.104565. Epub 2022 Oct 7.
The complement system is an important immune defense mechanism that plays essential roles in both innate and adaptive immunity of vertebrates. Since complement components are identified in deuterostome and even primitive protostome species, the origin and evolution of complement system in invertebrates have been of great interest. Recently, research on the complement system in mollusc immunity has been increasing due to their importance in worldwide aquaculture, and their phylogenetic position. Complement components including C3, C1q domain containing protein (C1qDCP), C-type lectin (CTL), ficolin-like, mannose-binding lectin (MBL)-associated serine proteases like (MASPL), and factor B have been identified, suggesting the existence of complement system in molluscs. The lectin pathway has been outlined in molluscs, which is initiated by CTL with CCP domain and MASPL protein to generate C3 cleavage fragments. The molluscan C1qDCP exhibits the capability to bind human IgG, indicating the existence of possible C1qDCP-mediated activation pathway in molluscs. The activation of C3 regulates the expressions of immune effectors (cytokines and antibacterial peptides), mediates the haemocyte phagocytosis, and inhibits the bacterial growth. Some MACPF domain containing proteins may replace the missing terminal pathway in molluscs. This article provides a review of complement system in molluscs, including its components, activation mechanisms and functions in the immune response of molluscs.
补体系统是一种重要的免疫防御机制，在脊椎动物的固有免疫和适应性免疫中都发挥着关键作用。由于在后口动物甚至原始原口动物物种中都发现了补体成分，因此无脊椎动物补体系统的起源和进化一直备受关注。近年来，由于贝类在全球水产养殖中的重要性及其系统发育地位，对贝类免疫中补体系统的研究不断增加。已经鉴定出包括C3、含C1q结构域蛋白（C1qDCP）、C型凝集素（CTL）、类纤维胶凝蛋白、甘露糖结合凝集素（MBL）相关丝氨酸蛋白酶样蛋白（MASPL）和B因子在内的补体成分，这表明贝类中存在补体系统。在贝类中已经勾勒出凝集素途径，该途径由具有CCP结构域的CTL和MASPL蛋白启动，以产生C3裂解片段。贝类的C1qDCP表现出与人IgG结合的能力，表明贝类中可能存在C1qDCP介导的激活途径。C3的激活调节免疫效应分子（细胞因子和抗菌肽）的表达，介导血细胞吞噬作用，并抑制细菌生长。一些含有MACPF结构域的蛋白可能替代贝类中缺失的末端途径。本文综述了贝类补体系统，包括其组成成分、激活机制及其在贝类免疫反应中的功能。
