Laboratory of Invertebrate Immunological Defense & Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China; and.
School of Life Sciences, East China Normal University, Shanghai, China.
J Immunol. 2022 May 15;208(10):2343-2362. doi: 10.4049/jimmunol.2101027. Epub 2022 May 4.
The C-type lectin family with the signature C-type lectin-like domain promotes antibacterial host defense within the animal kingdom. We examined the role of Chinese mitten crab, (H. Milne-Edwards) (Decapoda: Grapsidae) Ig domain-containing C-type lectin (IgLectin), a novel and poorly understood member of the C-type lectin family. was expressed primarily by both hemocytes ( ) and intestines, with significantly induced mRNA expression on intestinal or hemolymph bacterial infections. As a soluble protein, both its C-type lectin-like domain and the Ig domain were required for bacterial binding, bacterial agglutination, bacterial growth inhibition, and in vivo bacterial clearance. Polymeric IgLectin could be constructed via the disulfide bond in the Ig domain, significantly enhancing IgLectin antibacterial activity. IgLectin promoted bacterial phagocytosis in an Ig domain-dependent manner in hemocytes, while it controlled microbial homeostasis and protected against bacteria-induced inflammation in the intestine. Protein interaction studies revealed that the IgLectin Ig domain bound to the first Ig domain of the polymeric Ig receptor, which was essential for IgLectin-induced bacterial phagocytosis. The temporal sequence of cell interactions during intestinal inflammation is only beginning to be understood. In this article, we show that hemocyte-derived IgLectin entered the intestinal wall at the later phase of intestinal inflammation. Moreover, IgLectin protected the host against intestinal and hemolymph infections in a polymeric Ig receptor-dependent manner. Therefore, the IgLectin promoted bacterial clearance and protected against inflammatory disease through an independent or synergistic effect of hemocytes and intestines in invertebrates.
C 型凝集素家族具有特征性的 C 型凝集素样结构域，在动物王国中促进抗菌宿主防御。我们研究了中国绒螯蟹（H. Milne-Edwards）（十足目：Grapsidae）Ig 结构域包含 C 型凝集素（IgLectin）的作用，这是 C 型凝集素家族中的一个新的、了解甚少的成员。 在血细胞（ ）和肠道中主要表达，肠道或血淋巴细菌感染后其 mRNA 表达显著诱导。作为一种可溶性蛋白，其 C 型凝集素样结构域和 Ig 结构域都需要与细菌结合、细菌凝集、抑制细菌生长和体内清除细菌。通过 Ig 结构域中的二硫键可以构建聚合 IgLectin，显著增强 IgLectin 的抗菌活性。IgLectin 以 Ig 结构域依赖的方式在血细胞中促进细菌吞噬，同时控制微生物体内平衡并防止肠道中细菌诱导的炎症。蛋白质相互作用研究表明，IgLectin 的 Ig 结构域与聚合 Ig 受体的第一个 Ig 结构域结合，这对于 IgLectin 诱导的细菌吞噬是必需的。肠道炎症期间细胞相互作用的时间顺序才刚刚开始被理解。在本文中，我们表明血细胞衍生的 IgLectin 在肠道炎症的后期进入肠道壁。此外，IgLectin 以聚合 Ig 受体依赖的方式保护宿主免受肠道和血淋巴感染。因此，IgLectin 通过血细胞和肠道的独立或协同作用促进细菌清除并防止炎症性疾病，在无脊椎动物中。
