Ley V, Robbins E S, Nussenzweig V, Andrews N W
Department of Pathology, Kaplan Cancer Center, New York, New York.
J Exp Med. 1990 Feb 1;171(2):401-13. doi: 10.1084/jem.171.2.401.
The protozoan parasite Trypanosoma cruzi can infect many distinct mammalian cell types. The parasites enter cells through the formation of phagocytic vacuoles, but later are found free in the cytosol, where they multiply as amastigotes. Using transmission electron microscopy we found that within 2 h after infection 70% of the parasites, including examples of both mammalian forms (trypomastigotes and amastigotes), were inside partially disrupted vacuoles or free in the cytosol. We demonstrated that the pH of vacuoles containing recently interiorized parasites is acidic, through immunocytochemical localization of the acidotropic compound DAMP (18) in their interior. Increasing the vacuolar pH with chloroquine, ammonium chloride, methylamine, or monensin significantly inhibited the escape of the parasites into the cytosol. These results are compatible with the hypothesis that an acid-active hemolysin of T. cruzi (15) might be involved in the escape mechanism.
原生动物寄生虫克氏锥虫可感染多种不同的哺乳动物细胞类型。这些寄生虫通过形成吞噬泡进入细胞，但随后会在细胞质中自由存在，在那里它们以无鞭毛体的形式繁殖。利用透射电子显微镜，我们发现感染后2小时内，70%的寄生虫，包括两种哺乳动物形态（锥鞭毛体和无鞭毛体）的样本，处于部分破裂的液泡内或细胞质中自由存在。我们通过在含有最近内化寄生虫的液泡内部对酸亲和性化合物DAMP（18）进行免疫细胞化学定位，证明这些液泡的pH值呈酸性。用氯喹、氯化铵、甲胺或莫能菌素提高液泡pH值可显著抑制寄生虫逃逸到细胞质中。这些结果与克氏锥虫的一种酸活性溶血素（15）可能参与逃逸机制的假设相符。
