Rowland E, Luo H, McCormick T
Tropical and Geographical Disease Institute, Molecular and Cellular Biology Program, College of Osteopathic Medicine, Ohio University, Athens 45701.
J Parasitol. 1995 Feb;81(1):123-6.
A human isolate of Trypanosoma cruzi obtained from Guayaquil, Ecuador (Guayas strain) was examined for its infectivity of the resistant C57Bl/6 (B6) and the susceptible C3H (He) mouse strains and compared to infection with the known virulent Brazil strain. C3H mice were capable of surviving acute Guayas infection, whereas the Brazil infection was fatal for this mouse strain. Both C3H and B6 mice showed a greatly reduced (over 10-fold) parasitemia during Guayas infection compared to Brazil infection. Histologic examination of heart tissue from Guayas-infected B6 and C3H mice indicates little inflammation, unlike what is typically seen in B6 mice chronically infected with the Brazil strain. There appears to be no remarkable difference in the anti-parasite antibody responses (as measured by ELISA and western blot) in mice infected 100 days with Guayas or Brazil parasites. Western blot analysis of the anti-heart response indicates no response during Guayas infection to a 43-kDa heart tissue glycoprotein that is a target of antibodies from B6 mice infected with Brazil strain. The Guayas strain, therefore, provides an infection that generates a low parasitemia and strong anti-parasite responses in the absence of specific anti-heart autoimmunity and obvious myocarditis. In vitro infection characteristics of these 2 parasite strains were studied in cultures of macrophages, myocytes, and fibroblasts by microscopic examination of stained slide cultures. In both short-term (24 hr) and long-term (15 day) experiments, Brazil strain infection was shown to have a greater infection rate with a higher number of parasites per cell than Guayas infection for all host cell types.(ABSTRACT TRUNCATED AT 250 WORDS)
对从厄瓜多尔瓜亚基尔获得的一株克氏锥虫人体分离株（瓜亚斯株）进行了研究，检测其对抗性C57Bl/6（B6）和易感C3H（He）小鼠品系的感染性，并与已知的强毒株巴西株感染情况进行比较。C3H小鼠能够在瓜亚斯急性感染中存活，而巴西株感染对该小鼠品系是致命的。与巴西株感染相比，C3H和B6小鼠在瓜亚斯株感染期间的寄生虫血症均大幅降低（超过10倍）。对瓜亚斯株感染的B6和C3H小鼠心脏组织进行组织学检查发现炎症轻微，这与长期感染巴西株的B6小鼠的典型情况不同。在用瓜亚斯株或巴西株寄生虫感染100天的小鼠中，抗寄生虫抗体反应（通过ELISA和western blot检测）似乎没有显著差异。western blot分析抗心脏反应表明，在瓜亚斯株感染期间，针对一种43 kDa心脏组织糖蛋白没有反应，而该糖蛋白是感染巴西株的B6小鼠抗体的靶标。因此，瓜亚斯株感染导致寄生虫血症较低，且在没有特异性抗心脏自身免疫和明显心肌炎的情况下产生强烈的抗寄生虫反应。通过对染色玻片培养物进行显微镜检查，在巨噬细胞、心肌细胞和成纤维细胞培养物中研究了这两种寄生虫株的体外感染特性。在短期（24小时）和长期（15天）实验中，对于所有宿主细胞类型，巴西株感染均显示出比瓜亚斯株感染更高的感染率，每个细胞中的寄生虫数量更多。（摘要截短于250字）
