Hoover D L, Nacy C A, Meltzer M S
Cell Immunol. 1985 Sep;94(2):500-11. doi: 10.1016/0008-8749(85)90274-6.
Macrophages are pivotal cells in interactions of man and leishmania. Leishmanial disease results from intracellular infection of macrophages: parasitized cells are seen in smears or biopsy specimens of lesions; macrophages cultured in vitro support replication of parasites. Paradoxically, parasite destruction is also mediated by macrophages, which become highly cytotoxic after exposure to immune lymphocytes or their lymphokine (LK) products. The precise molecular mechanisms by which lymphocytes or LK induce macrophage activation for leishmanicidal activity, however, are not yet known. We analyzed interactions of leishmania amastigotes with human monocytes cultured in vitro as a nonadherent cell pellet. Leishmania donovani and L. major replicated in freshly isolated monocytes. Monocytes treated with greater than 200 IU/ml of the LK, human Interferon-gamma (IFN-gamma), destroyed tumor cells and L. donovani, but not L. major. Phorbol myristate acetate, endotoxic bacterial lipopolysaccharide, and recombinant human IFN-alpha and IFN-beta did not induce cytotoxicity. The time course for induction of cytotoxicity contrasted sharply with that of previously described monocyte antileishmanial activity: IFN-gamma induced cytotoxicity even when added after infection with L. donovani; induction of cytotoxicity did not require that IFN-gamma be present throughout the period of culture after infection: a 30-min preinfection pulse of IFN-gamma was sufficient to induce 70% of maximal activity; and freshly isolated monocytes and cells cultured for up to 4 days in vitro prior to infection and IFN-gamma treatment were equally responsive to IFN-gamma. These studies provide convincing evidence for intracellular cytotoxicity for L. donovani by freshly isolated human monocytes. This system provides an important base for further analysis of induction and expression of cytotoxic mechanisms against leishmania and other intracellular organisms that cause human disease.
巨噬细胞是人类与利什曼原虫相互作用中的关键细胞。利什曼病是由巨噬细胞的细胞内感染引起的：在病变的涂片或活检标本中可看到被寄生的细胞；体外培养的巨噬细胞支持寄生虫的复制。矛盾的是，寄生虫的破坏也由巨噬细胞介导，巨噬细胞在接触免疫淋巴细胞或其淋巴因子（LK）产物后会变得具有高度细胞毒性。然而，淋巴细胞或LK诱导巨噬细胞激活以产生杀利什曼原虫活性的确切分子机制尚不清楚。我们分析了利什曼原虫无鞭毛体与体外培养的人单核细胞（作为非贴壁细胞沉淀）之间的相互作用。杜氏利什曼原虫和硕大利什曼原虫在新鲜分离的单核细胞中复制。用大于200 IU/ml的LK（人干扰素-γ，IFN-γ）处理的单核细胞可破坏肿瘤细胞和杜氏利什曼原虫，但不能破坏硕大利什曼原虫。佛波酯肉豆蔻酸酯、内毒素性细菌脂多糖以及重组人IFN-α和IFN-β均未诱导细胞毒性。细胞毒性诱导的时间进程与先前描述的单核细胞抗利什曼原虫活性的时间进程形成鲜明对比：即使在感染杜氏利什曼原虫后添加IFN-γ也能诱导细胞毒性；细胞毒性的诱导并不要求IFN-γ在感染后的整个培养期都存在：感染前30分钟的IFN-γ脉冲足以诱导70%的最大活性；新鲜分离的单核细胞以及在感染和IFN-γ处理前体外培养长达4天的细胞对IFN-γ的反应相同。这些研究为新鲜分离的人单核细胞对杜氏利什曼原虫的细胞内细胞毒性提供了令人信服的证据。该系统为进一步分析针对利什曼原虫和其他引起人类疾病的细胞内生物体的细胞毒性机制的诱导和表达提供了重要基础。
