Grimwood J, Smith J E
Department of Pure and Applied Biology, University of Leeds, U.K.
Int J Parasitol. 1996 Feb;26(2):169-73. doi: 10.1016/0020-7519(95)00103-4.
The potential role of the 5 surface proteins of Toxoplasma gondii tachyzoites in host cell invasion was investigated using an in vitro neutralization assay. Supporting earlier findings, TG05.54, a monoclonal antibody recognizing the major surface protein SAG 1, was shown to cause a consistent and significant blockade of invasion into bovine kidney cells, indicating a functional role for this protein in host cell invasion. The neutralizing effect was only seen with certain anti-SAG 1 monoclonal antibodies, suggesting the presence of a functional ligand within the molecule. A second surface protein, SAG 2 was also shown to be involved in the invasion process. Anti-SAG 2 antibodies prevented parasite reorientation, leaving zoites immobilized on the host cell membrane and resulting in increased internalization of tachyzoites. Antibodies recognizing other surface, rhoptry, dense granule and microneme molecules had no effect on invasion.
利用体外中和试验研究了刚地弓形虫速殖子5种表面蛋白在宿主细胞侵袭中的潜在作用。与早期研究结果一致，识别主要表面蛋白SAG 1的单克隆抗体TG05.54被证明能持续且显著地阻断对牛肾细胞的侵袭，表明该蛋白在宿主细胞侵袭中发挥功能性作用。仅某些抗SAG 1单克隆抗体具有中和作用，提示该分子内存在功能性配体。第二种表面蛋白SAG 2也被证明参与侵袭过程。抗SAG 2抗体可阻止寄生虫重新定向，使子孢子固定在宿主细胞膜上，导致速殖子内化增加。识别其他表面、棒状体、致密颗粒和微线体分子的抗体对侵袭无影响。
