Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Krakow, Poland.
Cell Tissue Res. 2018 Mar;371(3):407-414. doi: 10.1007/s00441-018-2787-0. Epub 2018 Feb 5.
Invertebrate immunity is associated with natural mechanisms that include cellular and humoral elements, similar to those that play a role in vertebrate innate immune responses. Formation of extracellular traps (ETs) is a newly discovered mechanism to combat pathogens, operating not only in vertebrate leucocytes but also in invertebrate immune cells. The ET components include extracellular DNA (exDNA), antimicrobial proteins and histones. Formation of mammalian ETs depends on enzymes such as neutrophil elastase, myeloperoxidase, the citrullination of histones and protease activity. It was confirmed that coelomocytes-immunocompetent cells of the earthworm Eisenia andrei-are also able to release ETs in a protease-dependent manner, dependent or independent of the formation of reactive oxygen species and rearrangement of the cell cytoskeleton. Similar to vertebrate leukocytes (e.g., neutrophil), coelomocytes are responsible for many immune functions like phagocytosis, cytotoxicity and secretion of humoral factors. ETs formed by coelomocyte analogues to neutrophil ETs consist of exDNA, histone H3 and attached to these structures proteins, e.g., heat shock proteins HSP27. The latter fact confirms that mechanisms of ET release are conserved in evolution. The study on Annelida adds this animal group to the list of invertebrates capable of ET release, but most importantly provides insides into innate mechanisms of ET formation in lower animal taxa.
无脊椎动物的免疫与包括细胞和体液成分在内的天然机制有关，这些机制类似于在脊椎动物先天免疫反应中起作用的机制。细胞外陷阱（ETs）的形成是一种新发现的抵御病原体的机制，不仅在脊椎动物白细胞中发挥作用，也在无脊椎动物免疫细胞中发挥作用。ET 的组成部分包括细胞外 DNA（exDNA）、抗菌蛋白和组蛋白。哺乳动物 ET 的形成依赖于中性粒细胞弹性蛋白酶、髓过氧化物酶、组蛋白瓜氨酸化和蛋白酶活性等酶。已经证实，蚯蚓 Eisenia andrei 的免疫活性体腔细胞（coelomocytes）也能够以依赖蛋白酶的方式释放 ETs，这种方式依赖或不依赖活性氧的形成和细胞细胞骨架的重排。与脊椎动物白细胞（如中性粒细胞）类似，体腔细胞负责许多免疫功能，如吞噬作用、细胞毒性和体液因子的分泌。与中性粒细胞 ET 类似的体腔细胞形成的 ET 由 exDNA、组蛋白 H3 和附着在这些结构上的蛋白质组成，例如热休克蛋白 HSP27。后一事实证实，ET 释放的机制在进化中是保守的。环节动物的研究将这个动物群体添加到能够释放 ET 的无脊椎动物名单中，但更重要的是，它为低等动物分类群中 ET 形成的先天机制提供了深入了解。
