Kasper L H, Currie K M, Bradley M S
J Immunol. 1985 May;134(5):3426-31.
A purified Toxoplasma gondii tachyzoite membrane protein (P30) and a monoclonal antibody directed against this antigen were used to immunize mice. The P30 protein has an apparent m.w. of 30,000 and is the major radioiodinated tachyzoite membrane antigen identified by human and mouse antitoxoplasma antisera. Polyclonal and monoclonal antibody to the P30 antigen are parasiticidal in the presence of human serum. A series of mice were immunized with affinity column-purified P30 protein. This produced a dose-dependent, antigen-specific IgG and IgM response. The mice were challenged with the less virulent C strain tachyzoite. Immunized mice showed a statistically significant increase in mortality over nonimmunized control mice. In addition, vaccinated mice had an increased number of intracerebral tissue cysts when compared with the control group. Similar results were obtained with passive transfer immunization by using monoclonal antibody directed against the P30 antigen. Immunofluorescence assay of brain tissue cyst bradyzoites revealed a total absence of P30 antigen. Bradyzoites were also deficient in another major tachyzoite antigen of approximate m.w. 22,000 (P22). Mouse antibradyzoite serum absorbed with tachyzoites recognized bradyzoites but failed to identify tachyzoites. This suggests that there are stage-specific bradyzoite antigens of Toxoplasma gondii.
用纯化的刚地弓形虫速殖子膜蛋白（P30）和针对该抗原的单克隆抗体免疫小鼠。P30蛋白的表观分子量为30000，是人和小鼠抗弓形虫抗血清鉴定出的主要放射性碘化速殖子膜抗原。P30抗原的多克隆和单克隆抗体在人血清存在下具有杀寄生虫作用。用亲和柱纯化的P30蛋白免疫一系列小鼠。这产生了剂量依赖性的、抗原特异性的IgG和IgM反应。用毒力较弱的C株速殖子攻击小鼠。免疫小鼠的死亡率比未免疫的对照小鼠有统计学上的显著增加。此外，与对照组相比，接种疫苗的小鼠脑内组织囊肿数量增加。用针对P30抗原的单克隆抗体进行被动转移免疫也得到了类似结果。对脑组织囊肿缓殖子的免疫荧光分析显示完全不存在P30抗原。缓殖子还缺乏另一种表观分子量约为22000的主要速殖子抗原（P22）。用速殖子吸收的小鼠抗缓殖子血清能识别缓殖子，但不能识别速殖子。这表明刚地弓形虫存在阶段特异性的缓殖子抗原。
