Osorio Y, Travi B L, Palma G I, Saravia N G
Centro Internacional de Entrenamiento e Investigaciones Médicas CIDEIM, Cali, Colombia.
J Parasitol. 1995 Oct;81(5):687-93.
The existence of an intracellular stage of Trypanosoma rangeli in the vertebrate host was evaluated by experimental infection of the U937 histiocytic cell line with the San Agustín strain and the Ub66-5b clone. The identity of the parasites at the beginning and end of the experiments was confirmed through biological behavior in the vector and mammal hosts, isoenzymes, polymerase chain reaction (PCR), and monoclonal antibodies. Infectivity to U937 cells of T. rangeli obtained from culture and salivary glands was evaluated under different experimental conditions. These included 34 C vs. 37 C, opsonized vs. nonopsonized parasites, and 2, 4, 6, 24, 48, and 72 hr of cell-parasite contact. Trypanosoma rangeli adopted a characteristic nondividing amastigote-like form within U937 cells, which was different in size (P = 0.001) from Trypanosoma cruzi amastigotes. Culture forms of T. rangeli were more infective than parasites from salivary glands (P = 0.049) but were less infective than T. cruzi (P = 0.0001). Variations in temperature (34-37 C) and complement opsonization did not affect infectivity. Viability of intracellular forms was confirmed by feeding Rhodnius prolixus with T. rangeli-infected cells. Resistance of T. rangeli to the intracellular milieu could be an important mechanism in producing chronic infections in mammals and in the infection of triatomines.
通过用圣奥古斯丁株和Ub66 - 5b克隆对U937组织细胞系进行实验性感染，评估了克氏锥虫在脊椎动物宿主体内细胞内阶段的存在情况。通过在媒介宿主和哺乳动物宿主中的生物学行为、同工酶、聚合酶链反应（PCR）以及单克隆抗体，确认了实验开始和结束时寄生虫的身份。在不同实验条件下，评估了从培养物和唾液腺获得的克氏锥虫对U937细胞的感染性。这些条件包括34℃与37℃、调理素化与未调理素化的寄生虫，以及细胞与寄生虫接触2、4、6、24、48和72小时。克氏锥虫在U937细胞内呈现出一种特征性的非分裂无鞭毛体样形态，其大小与克氏锥虫无鞭毛体不同（P = 0.001）。克氏锥虫的培养形式比来自唾液腺的寄生虫更具感染性（P = 0.049），但比克氏锥虫的感染性低（P = 0.0001）。温度变化（34 - 37℃）和补体调理作用不影响感染性。通过用感染了克氏锥虫的细胞喂食长红猎蝽，证实了细胞内形式的活力。克氏锥虫对细胞内环境的抗性可能是在哺乳动物中产生慢性感染以及在锥蝽感染中的一个重要机制。
