Gugssa A, Gebru S, Lee C M, Baccetti B, Anderson W
Department of Biology, Howard University, Washington, DC 20059, USA.
J Submicrosc Cytol Pathol. 2005 Aug;37(2):99-107.
Trypanosoma musculi-macrophage co-cultures were studied to investigate the biological role of lipopolysaccharide (LPS) induced cytokines in controlling the proliferation of parasites in vitro. Macrophages, isolated by peritoneal lavage, sustained the growth and proliferation of the parasites. Macrophages activated with LPS were characterized by up-regulation of nitric oxide synthase (iNOS) and phagocytosis of fluorescent latex spheres. Activated macrophages showed marked inhibition of the association and proliferation of the parasites. The LPS treated macrophages produced cytokines, especially interferon gamma (INF-gamma), which was detected by Western blot. Trypanosomes, inhibited from association with macrophages, did not proliferate and instead formed clusters held together by their flagella. Cells in these clusters were apoptotic, as demonstrated by the Apoptag reaction and gel fragmentation assay. In addition, high levels of caspase 8 and caspase 3 were shown in floating trypanosome clusters. The results would suggest that INF-gamma and other cytokines released by activated macrophages, possibly functioning through the INF-gammaR1, Fas ligand, CD95 or other death ligands in the trypanosome plasma membrane initiates the apoptosis cascade in trypanosomes.
研究了小鼠锥虫与巨噬细胞的共培养，以探讨脂多糖（LPS）诱导的细胞因子在体外控制寄生虫增殖中的生物学作用。通过腹腔灌洗分离的巨噬细胞支持寄生虫的生长和增殖。用LPS激活的巨噬细胞的特征在于一氧化氮合酶（iNOS）的上调和荧光乳胶球的吞噬作用。活化的巨噬细胞对寄生虫的黏附和增殖表现出明显的抑制作用。经LPS处理的巨噬细胞产生细胞因子，尤其是通过蛋白质免疫印迹法检测到的干扰素γ（INF-γ）。被抑制与巨噬细胞黏附的锥虫不增殖，而是形成由其鞭毛聚集在一起的簇。如凋亡检测反应和凝胶片段化分析所示，这些簇中的细胞是凋亡的。此外，在漂浮的锥虫簇中显示出高水平的半胱天冬酶8和半胱天冬酶3。结果表明，活化的巨噬细胞释放的INF-γ和其他细胞因子可能通过锥虫细胞膜中的INF-γR1、Fas配体、CD95或其他死亡配体发挥作用，从而启动锥虫的凋亡级联反应。
