伯氏疟原虫感染早期的根治性治疗对再感染细胞免疫应答的影响

目的探讨疟疾感染早期根治性治疗对再感染细胞免疫应答的影响。方法用伯氏疟原虫感染DBA/2小鼠,感染后3d进行根治性治疗,并于初次感染后90d进行再感染。通过吉姆萨薄血膜染色法计数红细胞感染率,流式细胞术检测再感染前（0d）和再感染后（1、3、5d）不同时间点脾T细胞中活化性T细胞百分含量,ELISA检测脾细胞培养上清中IFN-γ、TNF-α、IL-4和IL-10水平。结果同源疟原虫再感染后,根治性治疗小鼠仅出现短暂的低水平虫体血症;再感染后第1～5天活化性T细胞百分率持续升高。IFN-γ于再感染后第1天即出现有意义的升高,第3天达到峰值水平,与此同时,TNF-α和IL-10水平也开始出现有意义的升高,但IL-4的升高出现在再感染后的第5天。结论疟疾感染早期的根治性治疗并不影响宿主在再感染时产生有效的细胞免疫应答,CD4＋Th1应答反应也是抵御疟疾再感染的关键因素之一。

Effect of early radical treatment of primary infection with Plasmodium berghei ANKA on the cellular immune response to homologous reinfection

Objective To investigate the effect of early radical treatment of primary Plasmodium infection on the cellular immune response to homologous reinfection.Methods DBA/2 mice were infected by intraperitoneal injection of 1×106 P.berghei ANKA parasitized erythrocytes.The mice were then radically treated with chloroquine plus artesunate at day-3 after infection.After primary infection,the mice were reinfected with P.berghei ANKA at day-90.The level of parasitemia during primary and secondary infections was determined by the Giemsa staining of thin blood smears.Flow cytometric method was used to quantitively analyze the percentage of activated T cells in spleen at day-0,1,3 and 5 post-reinfection.The levels of IFN-γ,TNF-α,IL-4 and IL-10 in the spleen cell culture supernatant were measured by ELISA.Results Parasitemia in radically treated mice was transient and extremely low.And the percentage of activated T cells was steadily increased from day-1 to day-5 after reinfection.The levels of IFN-γ was significantly increased at day-1 post-reinfection and reached the peak at day-3 post-reinfection.Similarly,TNF-α and IL-10 were also significantly increased.IL-4 was significantly increased at day-5 post-reinfection.Conclusion Early radical treatment of primary Plasmodium infection has little effect on the cellular immune response to homologous reinfection.CD4＋ Th1 response may also be a key factor involved in protective immunity against homologous reinfection.