弓形虫主要表膜P30抗原的免疫保护作用研究

Studies on the immune protective effects of the major surface antigen P30 of Toxoplasma gondii

目的 研究弓形虫主要表膜P30抗原免疫小鼠所诱导的免疫性保护作用及免疫保护机制。方法 将单克隆抗体免疫亲和层析分离纯化的P30抗原免疫C57BL/ 6纯系小鼠 ,然后用弓形虫RH株速殖子和Fukaya株包囊攻击感染 ,观察P30抗原免疫对急性弓形虫感染鼠死亡时间及慢性感染鼠脑内包囊形成的影响 ,同时对感染后不同时间鼠血清特异性抗体水平、IL 2及IFN r细胞因子水平和脾T淋巴细胞亚群的动态变化进行了测试分析。结果 显示P30抗原免疫可在一定程度上延长感染小鼠的存活时间 ,减少脑内包囊的形成数量 ,增强小鼠抵抗急慢性弓形虫感染的能力。在感染后不同时期免疫鼠血清中特异性抗体水平及IFN r、IL 2水平均高于同期对照鼠 ,而且免疫鼠脾CD4 + 和CD8+ T淋巴细胞尤其是CD8+ 细胞的数量在感染早期升高较快 ,至感染后第 4周达高峰 ,两者的比值随感染时间的延长而逐渐下降。结论 P30抗原免疫对感染小鼠具有明显的保护作用 ,是细胞免疫和体液免疫共同作用的结果 。

Objective: To study the immune effects and the protective mechanism by immunizing mice to the major antigen P30 of Toxoplasma gondii. Methods: C 57BL/6 mice were immunized with the P30 antigen of Toxoplasma which was purified by the McAb affinity chromitography technique, Then the mice were infected with RH tachyzoites and FuKaya cysts of Toxoplasma respectively. The death time and the number of cysts in the mices brain were recorded during the acute and chronic infection. At the same time, the level of specific antibody and cytokines and the changes of spleen T lymphocytes subgroup were detected. Results: The immunization of P30 antigen obviously prolonged the survial time of the mice and reduced the number of cysts in brain and enhanced the ability against the acute and chronic infection. The level of specific antibody and IFN-r,IL-2 of the immunized mice in various periods after the infection were higher than that of the control group. The number of CD 4+ and CD 8+T lymphocytes of immunized mice increased ,especially the CD 8+ cells, which reached its highest point in 4 weeks after the infection and the CD 4+/CD 8+ cell ratio gradually decreased along with the infective time. Conclusion: The immunization of P30 antigen can have significant protective efffct on infective mice and the T、Bcell-mediated immunity contributes to this effect, especially the cellular immune response.