Rimoldi M T, Cardoni R L, Olabuenaga S E, de Bracco M M
Immunology. 1981 Apr;42(4):521-7.
We have studied the relationship between phagocytosis and cytotoxicity of human polymorphonuclear leucocytes (PMN) to sensitized Trypanosoma cruzi. Assays were done simultaneously using [3H]-uridine labelled epimastigotes as target cells. Phagocytosis was evaluated by the uptake and cytotoxicity by the release of parasite associated [3H]-uridine. Both reactions reached maximum levels at the same effector- to target-cell ratio and antibody concentration. Uptake of epimastigotes by PMN was highest at 30 min and intracellular disruption and release of parasite debris took place later. In conditions that precluded repeated uptake of sensitized radiolabelled T. cruzi, the release profile of [3H]-uridine from PMN that contained intracellular parasites was similar to that of the standard cytotoxic assay. However, as the ingestion phase was separated from the release step, no lag in the onset of the reaction was observed. Although we cannot rule out extracellular killing, the results of this study demonstrate that the bulk of damaged T. cruzi epimastigotes had been previously internalized by the PMN.
我们研究了人类多形核白细胞（PMN）对致敏克氏锥虫的吞噬作用与细胞毒性之间的关系。使用[3H]-尿苷标记的无鞭毛体作为靶细胞同时进行检测。通过摄取来评估吞噬作用，通过寄生虫相关[3H]-尿苷的释放来评估细胞毒性。两种反应在相同的效应细胞与靶细胞比例和抗体浓度下达到最高水平。PMN对无鞭毛体的摄取在30分钟时最高，细胞内破坏和寄生虫碎片的释放随后发生。在排除对致敏放射性标记克氏锥虫重复摄取的条件下，含有细胞内寄生虫的PMN中[3H]-尿苷的释放曲线与标准细胞毒性检测的曲线相似。然而，由于摄取阶段与释放步骤分开，未观察到反应开始时有滞后现象。虽然我们不能排除细胞外杀伤作用，但本研究结果表明，大部分受损的克氏锥虫无鞭毛体此前已被PMN内化。
