New types of clotting factors and defense molecules found in horseshoe crab hemolymph: their structures and functions.
New types of clotting factors and defense molecules found in horseshoe crab hemolymph: their structures and functions.
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DOI：
10.1093/oxfordjournals.jbchem.a021894
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发表时间：
1998
影响因子：
2.7
通讯作者：
S. Iwanaga;S. Kawabata;T. Muta
中科院分区：
文献类型：
--
作者：
S. Iwanaga;S. Kawabata;T. Muta
缺乏适应性免疫系统的无脊椎动物已经形成了防御系统，即所谓的天然免疫，对潜在病原体表面的共同抗原做出反应。一种这样的防御系统与马蹄蟹血细胞对入侵者的细胞反应有关。血细胞含有两种类型的分泌颗粒，大的(L)和小的(S)，这些颗粒的内容物通过胞吐作用对入侵的微生物做出反应而释放。最近对L颗粒和S颗粒的颗粒成分的生化和免疫学研究表明，这两种颗粒选择性地存储参与宿主防御系统的颗粒特异性蛋白。L颗粒含有血淋巴凝血所必需的所有凝血因子、蛇毒和半胱氨酸蛋白酶抑制剂、抗脂多糖因子和几种具有内毒素结合和细菌凝集活性的速凝素。另一方面，S颗粒含有多种新的富含半胱氨酸的具有抗菌或细菌凝集活性的碱性蛋白，如速殖子蛋白、大防御素、速粘菌素和速他汀类。这些蛋白在颗粒中的共存及其释放到血淋巴中表明它们协同作用构建了有效的宿主防御系统来抵御入侵者。本文综述了中华绒螯蟹(Tachypleus Tridentatus)中发现的这些新型防御分子的结构和功能。
Invertebrate animals, which lack adaptive immune systems, have developed defense systems, so-called innate immunity, that respond to common antigens on the surface of potential pathogens. One such defense system is involved in the cellular responses of horseshoe crab hemocytes to invaders. Hemocytes contain two types, large (L) and small (S), of secretory granules, and the contents of these granules are released in response to invading microbes via exocytosis. Recent biochemical and immunological studies on the granular components of L- and S-granules demonstrated that the two types of granules selectively store granule-specific proteins participating in the host defense systems. L-Granules contain all the clotting factors essential for hemolymph coagulation, protease inhibitors including serpins and cystatin, and anti-lipopolysaccharide (LPS) factor and several tachylectins with LPS binding and bacterial agglutinating activities. On the other hand, S-granules contain various new cysteine-rich basic proteins with antimicrobial or bacterial agglutinating activities, such as tachyplesins, big defensin, tachycitin, and tachystatins. The co-localization of these proteins in the granules and their release into the hemolymph suggest that they serve synergistically to construct an effective host defense system against invaders. Here, the structures and functions of these new types of defense molecules found in the Japanese horseshoe crab (Tachypleus tridentatus) are reviewed.