Ruiz R de C, Rigoni V L, Gonzalez J, Yoshida N
Department of Microbiology, Immunology and Parasitology, Escola Paulista de Medicina, São Paulo, Brazil.
Parasite Immunol. 1993 Feb;15(2):121-5. doi: 10.1111/j.1365-3024.1993.tb00591.x.
We have previously shown that monoclonal antibodies directed to the 90 kDa glycoprotein and the 35/50 kDa glycoconjugate, present on the surface of Trypanosoma cruzi metacyclic trypomastigotes, inhibited host cell invasion. Here we investigated whether these molecules could be the ligands for the target cell receptor. Binding assays were performed by incubating Vero cells with sonicated parasite extract. Detection of bound parasite components was carried out by using monoclonal antibodies (MoAbs) IG7 and 10D8, which recognize the 90 kDa and the 35/50 kDa antigens respectively. These experiments revealed that the 35/50 kDa glycoconjugate of metacyclic forms, but not the 1G7-reactive antigen, binds to Vero cells. The purified 35/50 kDa antigen bound to Vero cells and inhibited the entry of metacyclic forms in a dose-dependent manner. Although to a lesser extent, an immunologically related 35/50 kDa antigen of non-infective epimastigotes also bound to Vero cells but it was unable to inhibit parasite penetration at a concentration (100 micrograms/ml) in which metacyclic antigen exhibited more than 60% inhibition. All these data suggest that the metacyclic 35/50 kDa surface glycoconjugate is a ligand to the host cell in the process of T. cruzi invasion.
我们之前已经表明，针对克氏锥虫循环后期锥鞭毛体表面存在的90 kDa糖蛋白和35/50 kDa糖缀合物的单克隆抗体可抑制宿主细胞入侵。在此，我们研究了这些分子是否可能是靶细胞受体的配体。通过将Vero细胞与超声破碎的寄生虫提取物孵育来进行结合试验。使用分别识别90 kDa和35/50 kDa抗原的单克隆抗体（MoAbs）IG7和10D8来检测结合的寄生虫成分。这些实验表明，循环后期形式的35/50 kDa糖缀合物而非IG7反应性抗原与Vero细胞结合。纯化的35/50 kDa抗原与Vero细胞结合，并以剂量依赖的方式抑制循环后期形式的进入。尽管程度较轻，但非感染性前鞭毛体的一种免疫相关的35/50 kDa抗原也与Vero细胞结合，但在循环后期抗原表现出超过60%抑制作用的浓度（100微克/毫升）下，它无法抑制寄生虫的穿透。所有这些数据表明，循环后期的35/50 kDa表面糖缀合物在克氏锥虫入侵过程中是宿主细胞的配体。
