CHARACTERIZATION OF PHOSPHOGLYCAN-CONTAINING SECRETORY PRODUCTS OF LEISHMANIA
CHARACTERIZATION OF PHOSPHOGLYCAN-CONTAINING SECRETORY PRODUCTS OF LEISHMANIA
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DOI：
10.1017/s0031182000075739
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发表时间：
1994-01-01
期刊：
影响因子：
2.4
通讯作者：
OVERATH, P
中科院分区：
文献类型：
--
作者：
ILG, T;STIERHOF, YD;OVERATH, P
本文概述了几种利什曼原虫在昆虫和哺乳动物阶段分泌的含磷酸聚糖的成分，利什曼原虫是新旧世界利什曼病的病原体。首先，所考虑的所有三个物种的前鞭毛体，墨西哥乳杆菌、多诺瓦尼乳杆菌和硕大乳杆菌，可能通过从细胞表面释放胶束而将脂磷酸聚糖（LPG）释放到培养基中。与细胞相关的 LPG 一样，培养物上清液 LPG 是两亲性的，由连接到物种特异性磷酸糖重复序列和寡糖帽的溶血烷基磷脂酰肌醇磷酸核心组成。其次，所有三个物种都释放亲水性磷酸聚糖。第三，所有三个物种似乎都分泌由磷酸糖重复序列和寡糖帽共价修饰的蛋白质。在墨西哥乳杆菌的前鞭毛体中，这些成分被组织为从鞭毛袋释放的两种丝状聚合物：由 100 kDa 磷酸糖蛋白和含蛋白质的高分子量磷酸聚糖 (proteo-HMWPG) 组成的分泌酸性磷酸酶 (sAP) 和同样由可能与蛋白质连接的磷酸聚糖组成的纤维网络。结构分析和基因克隆表明，寄生虫可以通过附着寡糖封端的磷酸糖重复序列来共价修饰富含丝氨酸和苏氨酸残基的蛋白质区域。我们认为体外形成的网络对应于先前在受感染白蛉消化道中展示的纤维材料。就杜氏乳杆菌而言，sAP 也被磷酸聚糖修饰，但既不包含蛋白 HMWPG，也不聚集成丝。最后，墨西哥乳杆菌无鞭毛体通过鞭毛袋将蛋白质-HMWPG 释放到受感染巨噬细胞的寄生液泡中。当受感染巨噬细胞在病变发展过程中破裂时，这种物质似乎被释放到受感染哺乳动物的组织中。这种分泌产物可能有助于病变发展的病理学。
This article presents an overview on phosphoglycan-containing components secreted by the insect and mammalian stages of several species of Leishmania, the causative agents of leishmaniasis in the Old and New World. Firstly, promastigotes of all three species considered, L. mexicana, L. donovani and L. major, shed lipophosphoglycan (LPG) into the culture medium possibly by release of micelles from the cell surface. Like the cell-associated LPG, culture supernatant LPG is amphiphilic and composed of a lysoalkylphosphatidylinositol-phosphosaccharide core connected to species-specific phosphosaccharide repeats and oligosaccharide caps. Secondly, all three species release hydrophilic phosphoglycan. Thirdly, all three species appear to secrete proteins covalently modified by phosphosaccharide repeats and oligosaccharide caps. In the case of promastigotes of L. mexicana, these components are organized as two filamentous polymers released from the flagellar pocket: the secreted acid phosphatase (sAP) composed of a 100 kDa phosphoglycoprotein and a protein-containing high-molecular-weight-phosphoglycan (proteo-HMWPG) and fibrous networks likewise composed of phosphoglycan possibly linked to protein. Structural analyses and gene cloning suggest that the parasites can covalently modify protein regions rich in serine and threonine residues by the attachment of phosphosaccharide repeats capped by oligosaccharides. We propose that the networks formed in vitro correspond to fibrous material previously demonstrated in the digestive tract of infected sandflies. In the case of L. donovani, the sAP is also modified by phosphoglycans but contains neither proteo-HMWPG nor does it aggregate to filaments. Finally, L. mexicana amastigotes release proteo-HMWPG via the flagellar pocket into the parasitophorous vacuole of infected macrophages. This material appears to be released into the tissue of the infected mammal upon rupture of infected macrophages during lesion development. This secretory product may contribute to the pathology of lesion development.