DEVELOPMENTAL ADAPTATIONS OF TRYPANOSOMA CRUZI TO THE VERTEBRATE IMMUNE SYSTEM

在这个项目中，我们一直在研究 克氏锥虫对脊椎动物宿主，特别是表面 在外鞭毛体形态发生期间发生的膜变化（载体 阶段）到亚周期锥鞭毛体（脊椎动物阶段）。 的是报表 在此期间，我们继续研究亚循环的机制， 锥虫鞭毛体通过替代途径对裂解产生抗性， 补体（ACP）。 对纯化补体成分的研究显示， 与上鞭毛体相比，后环锥鞭毛体 最小量的因子B，ACP中的一种必需辅因子。 在 相反，与其他系统获得的结果相比， 调节组分H在激活上鞭毛体方面是等效的， 非活化的后环锥鞭毛体。 酶处理研究 表明亚循环锥鞭虫无法激活 ACP是由于它们对链霉蛋白酶和衣霉素敏感 分子。 在相关研究中，我们研究了72，000 MN的表达， 糖蛋白（GP72）（我们以前曾证明是C3的受体， 上鞭毛体）对昆虫和培养物衍生的后环锥鞭毛体的作用。 用单克隆抗体检测到GP72存在于昆虫细胞表面， 代谢物，但没有发现的文化产生的生物体。 因为通过 表面标记和免疫沉淀，我们能够检测到 分子在这个阶段，它显然是修改和表达较少 抗原表位接近抗体结合完整的寄生虫比其 相当于上鞭毛体。 最后，使用兔抗独特型抗体， 抗GP72单克隆抗体，我们能够提高抗体反应 针对小鼠、兔和小鼠中GP72分子上的碳水化合物决定簇， 豚鼠

In this project, we have been studying developmental adaptations of Trypanosoma cruzi to the vertebrate host, and in particular, surface membrane changes occuring during the morphogenesis of epimastigotes (vector stage) to metacyclic trypomastigotes (vertebrate stage). During the report period, we continued to investigate the mechanism by which metacyclic trypomastigotes become resistant to lysis by the alternative pathway of complement (ACP). Studies with purified complement components revealed that in comparison to epimastigotes, metacyclic trypomastigotes bind minimal amounts of Factor B, an essential co-factor in the ACP. In contrast, to the findings obtained with other systems, binding of the regulatory component H was equivalent in activating epimastigotes and non-activating metacyclic trypomastigotes. Enzyme treatment studies suggested that the incapacity of metacyclic trypomastigotes to activate the ACP was due to their elaboration of pronase and tunicamycin sensitive molecules. In related studies, we investigated the expression of a 72,000 MN glycoprotein (GP72) (previously shown by us to be the acceptor for C3 on epimastigotes) on insect and culture derived metacyclic trypomastigotes. Using monoclonal antibodies, GP72 was detected on the surface of insect metacyclics but was not found on culture generated organisms. Since by surface labelling and immunoprecipitation we were able to detect the molecule on this stage, it apparently is modified and expresses fewer epitopes accessible to antibody binding on intact parasites than its equivalent on epimastigotes. Finally, using rabbit anti-idiotypic antibodies directed against an anti-GP72 monoclonal antibody, we were able to raise an antibody response against carbohydrate determinants on the GP72 molecule in mice, rabbits and guinea pigs.