IL-10在Plasmodium yoelii 17XL和Plasmodium chabaudi AS疟原虫混合感染宿主病理损伤中的作用研究

The Role of IL-10 on the Host Pathological Injury in DBA/2 Mice Mixed Infection with Plasmodium yoelii 17XL and Plasmodium chabaudi AS

为探讨IL-10在致死型约氏疟原虫(Plasmodium yoelii 17XL,P.y17XL)和夏氏疟原虫(Plasmodiumchabaudi AS,P.cAS)混合感染宿主病理损伤中的作用,用P.y17XL、P.cAS和P.y17XL+P.cAS分别感染DBA/2小鼠,计数红细胞感染率;感染后第3、5、8、10、12和19天分别尾静脉取血,肝素抗凝后短暂离心,采用高纯度DNA提取试剂盒抽提DNA,实时定量PCR检测虫负荷水平;感染后第0、1、3、5、8、10、12和15天制备脾细胞悬液,ELISA检测脾细胞培养上清中IL-10水平。实验结果发现,P.y17XL单独感染和混合感染小鼠IL-10水平在感染后第5天和第8天分别达峰值,随后开始下降至正常水平,小鼠虫血症均达中等水平,存活率100%;相比P.cAS感染小鼠IL-10在感染后第3天突然出现高水平升高并且维持时间较长;于感染后第8天达峰值,是同天P.y17XL单独感染和混合感染小鼠IL-10水平的2倍,虫血症水平较高,小鼠全部死亡。同时实时定量PCR结果发现,混合感染小鼠,于感染后3～12 d P.y17XL增殖占优势,而感染后15～19 d则P.cAS增殖处于优势状态。表明以IL-10为核心的免疫调节网络与疟疾感染过程中病理损伤密切相关。同时提示混合感染小鼠应答模式与P.y17XL感染小鼠的应答模式相同。

In order to investigate the role of IL-10 on the host pathological injury mixed infection with lethal Plasmodium yoelii 17XL （P.yl7XL） and Plasmodium chabaudi AS （P.cAS） , DBA/2 mice were infected with P.yI7XL, P.cAS, or P.yI7XL ＋ P. cAS respectively, and counted the infection rate of erythroeytes for each group of mice. Parasitemia and mortality were monitored daily. Tail blood collected at different time points was anti-coagulated by heparin on day 3, 5, 8, I0, 12 and 19 post infection （PI） and centrifuged briefly for DNA extraction using a high pure blood genome DNA extraction kit, real-time quantitative （RTQ） PCR for determining the level of parasite burden. On day 0, 1, 3, 5, 8, 10, 12 and 15 PI splenocyte IL-10 were dynamically detected by ELISA. The results showed that the level of IL-10 in DBA/2 mice infected by P. yl7XL alone and the mixed infection got its peak on day 5 and 8 PI, and then began to decline to normal level, parasitemia reached a middle level, the survival rate was 100% ; comparatively the IL-10 level in DBA/2 mice infected by P. cAS increased suddenly on day 3 PI and then maintained a fairly long time, and reached a peak on day 8 PI and contained 2 times higher than that of the other infected mice on the same day, and then all mice died. At the same time it was found the RTQ-PCR results that in DBA/2 mice, P.ylTXL proliferalion predominated from day 3～12 PI, however, on days 15～19 PIP. cAS proliferation laid predominance. Indicated that IL-10 as the core of the immune regulatory network closely correlated with the pathological injury in malaria infection process. At the same time, it was pointed out that the immune response mode in P.ylTXL infection mice was the same as the one in the mixed infection mice.