Chang K P, Dwyer D M
J Exp Med. 1978 Feb 1;147(2):515-30. doi: 10.1084/jem.147.2.515.
An in vitro system was developed for studying host-parasite cellular interactions in visceral leishmaniasis with amastigotes isolated from infected spleens of hamsters and their peritoneal macrophages maintained by an improved method. The culture system supports the growth of Leishmania donovani amastigotes with different parasite/macrophage ratios for up to 2 wk, yielding results more consistent and reproducible than previously possible. Results indicated that the "forms" of the amastigotes (with or without adherent host membranes) and the "state" of the macrophages (with or without stimulation in vivo by thioglycollate or in vitro by aging) had no effect on the growth rate of the parasites, which, however, seems to vary with the macrophage subpopulations. An electron microscope study suggests that amastigotes are ingested through phagocytosis by the macrophages and become lodged in loose phagosomes. Additional evidence with quantitative data is presented to support the earlier findings that phagosome-lysosome fusion occurs after the interiorization of the parasites and that they not only survive but multiply in these vacuoles. During the postinfection periods, reorientation of amastigotes in vacuolar space results in the appearance of three types of parasitophorous vacuoles (parasites in loose vacuoles, in tight-fitting vacuoles or abutting in part against the inner lining of vacuoles). The last category may be the predominant type giving rise to the variations observed. Exogenously introduced dense marker accumulated in these parasitophorous vacuoles of the macrophages infected for several days indicating a continuous accessibility of amastigotes to the ambient mestruum via phagosome-lysosome vacuolar system of the host cells. This finding may have significant implications in parasite nutrition, host immunity, and chemotherapy of leishmaniasis.
我们开发了一种体外系统，用于研究内脏利什曼病中宿主 - 寄生虫细胞间的相互作用。该系统使用从感染仓鼠脾脏分离出的无鞭毛体及其通过改良方法维持的腹膜巨噬细胞。该培养系统支持杜氏利什曼原虫无鞭毛体在不同寄生虫/巨噬细胞比例下生长长达2周，产生的结果比以前更一致且可重复。结果表明，无鞭毛体的“形态”（有无附着的宿主膜）和巨噬细胞的“状态”（体内是否经巯基乙酸刺激或体外是否经老化刺激）对寄生虫的生长速率没有影响，然而，寄生虫的生长速率似乎因巨噬细胞亚群而异。电子显微镜研究表明，无鞭毛体通过巨噬细胞的吞噬作用被摄取并滞留在疏松的吞噬体中。还提供了定量数据的额外证据，以支持早期的发现，即寄生虫内化后吞噬体 - 溶酶体融合发生，并且它们不仅在这些液泡中存活而且繁殖。在感染后的时期，无鞭毛体在液泡空间中的重新定向导致出现三种类型的寄生泡（寄生虫在疏松液泡中、紧密贴合的液泡中或部分紧靠液泡内衬）。最后一类可能是导致观察到的变异的主要类型。外源性引入的致密标记物积聚在感染数天的巨噬细胞的这些寄生泡中，表明无鞭毛体通过宿主细胞的吞噬体 - 溶酶体液泡系统持续接触周围的月经血。这一发现可能对利什曼病的寄生虫营养、宿主免疫和化疗具有重要意义。
