Almeida-de-Faria M, Freymüller E, Colli W, Alves M J
Departamento de Bioquímica, Instituto de Química.
Exp Parasitol. 1999 Aug;92(4):263-74. doi: 10.1006/expr.1999.4423.
Almeida-de-Faria, M., Freymüller, E., Colli, W., and Alves, M. J. M. 1999. Trypanosoma cruzi: Characterization of an intracellular epimastigote-like form. Experimental Parasitology 92, 263-274. A detailed study of transient epimastigote-like forms as intermediates in the differentiation of Trypanosoma cruzi amastigotes to trypomastigotes inside the host cell cytoplasm was undertaken using the CL-14 clone grown in cells maintained at 33 degrees C. Several parameters related to these forms have been compared with epimastigotes and other stages of the parasite. Consequently, the designation of intracellular epimastigotes is proposed for these forms. Despite being five times shorter (5.4 +/- 0.7 micrometer) than the extracellular epimastigote (25.2 +/- 2.1 micrometer), the overall morphology of the intracellular epimastigote is very similar to a bona fide epimastigote, when cell shape, position, and general aspect of organelles are compared by transmission electron microscopy. Epimastigotes from both sources are lysed by human complement and bind to DEAE-cellulose, in contrast to amastigotes and trypomastigote forms. A monoclonal antibody (3C5) reacts with both epimastigotes either isolated from axenic media or intracellular and very faintly with amastigotes, but not with trypomastigotes. Some differences of a quantitative nature are apparent between the two epimastigote forms when reactivities with lectins or stage-specific antibodies are compared, revealing the transient nature of the intracellular epimastigote. The epitope recognized by 3C5 monoclonal antibody reacts slightly more intensely with extracellular than with intracellular epimastigotes, as detected by immunoelectron microscopy. Also a very faint reaction of the intracellular epimastigotes was observed with monoclonal antibody 2C2, an antibody which recognizes a glycoprotein specific for the amastigote stage. Biological parameters as growth curves in axenic media and inhability to invade nonphagocytic tissue-cultured cells are similar in the epimastigotes from both origins. It is proposed that the epimastigote-like forms are an obligatory transitional stage in the transformation of amastigotes to trypomastigotes with a variable time of permanency in the host cell cytoplasm depending on environmental conditions.
阿尔梅达 - 德 - 法里亚，M.，弗雷米勒，E.，科利，W.，以及阿尔维斯，M. J. M. 1999年。克氏锥虫：一种细胞内类上鞭毛体形态的特征。《实验寄生虫学》92卷，第263 - 274页。利用在33摄氏度培养的细胞中生长的CL - 14克隆，对作为克氏锥虫无鞭毛体在宿主细胞胞质内分化为上鞭毛体过程中的中间阶段的短暂类上鞭毛体形态进行了详细研究。已将与这些形态相关的几个参数与上鞭毛体及该寄生虫的其他阶段进行了比较。因此，建议将这些形态命名为细胞内上鞭毛体。尽管细胞内上鞭毛体比细胞外上鞭毛体（25.2±2.1微米）短五倍（5.4±0.7微米），但通过透射电子显微镜比较细胞形状、位置和细胞器的总体外观时，细胞内上鞭毛体的整体形态与真正的上鞭毛体非常相似。与无鞭毛体和上鞭毛体形态不同，来自这两种来源的上鞭毛体都能被人补体溶解并结合到二乙氨基乙基纤维素上。一种单克隆抗体（3C5）与从无细胞培养基中分离的上鞭毛体以及细胞内上鞭毛体都发生反应，与无鞭毛体反应很微弱，但与上鞭毛体不反应。当比较与凝集素或阶段特异性抗体的反应性时，两种上鞭毛体形态在数量性质上存在一些差异，这揭示了细胞内上鞭毛体的短暂性质。通过免疫电子显微镜检测，3C5单克隆抗体识别的表位与细胞外上鞭毛体的反应强度略高于细胞内上鞭毛体。还观察到细胞内上鞭毛体与单克隆抗体2C2有非常微弱的反应，2C2抗体识别一种无鞭毛体阶段特异性的糖蛋白。两种来源的上鞭毛体在无细胞培养基中的生长曲线以及无法侵入非吞噬性组织培养细胞等生物学参数相似。有人提出，类上鞭毛体形态是无鞭毛体转化为上鞭毛体过程中的一个必经过渡阶段，在宿主细胞胞质内的持续时间因环境条件而异。
