摘要
目的探讨致死型约氏疟原虫(Plasmodium yoelii 17XL,Py17XL)和夏氏疟原虫(Plasmodium chabaudi AS,PcAS)混合感染宿主免疫应答特点与病理损伤的相关性。方法分别用Py17XL、Pc AS和Py17XL+PcAS感染BALB/c小鼠,计数红细胞感染率;于感染后0、1、3、5、8、10、12和15d处死小鼠,取脾,制备脾细胞悬液,培养后采用ELISA检测脾细胞上清中IFN-γ和IL-4水平;分别于感染后3、5、8d尾静脉取血,肝素抗凝,短暂离心后采用高纯度DNA提取试剂盒抽提DNA,实时荧光定量PCR检测虫负荷。结果 Py17XL单独感染和Py17XL与PcAS混合感染小鼠IFN-γ水平分别在感染后第3d和5d升高,PcAS单独感染第5d小鼠IFN-γ水平是相同时间点Py17XL和混合感染小鼠的3倍;Py17XL单独感染和混合感染小鼠IL-4水平分别在感染后第3d和8d升高,PcAS感染小鼠于感染后第10d达峰值(P<0.01),此后回落,但仍维持在较高水平。PcAS感染小鼠原虫血症水平上升缓慢,于感染后第9d红细胞感染率达峰值,随后迅速下降,于感染后第14d自愈,小鼠生存率为100%;Py17XL感染小鼠原虫血症水平迅速升高,于感染后第5d红细胞感染率高达(50.57±9.12)%,小鼠于感染后第5d及次日全部死亡;混合感染小鼠原虫血症水平迅速升高,感染后第5d达峰值,第9d小鼠全部死亡。实时荧光定量PCR检测混合感染小鼠以Py17XL增殖占优势。结论抗疟保护性免疫依赖Th1和Th2型免疫应答的有效建立和协调过渡,免疫应答的模式与宿主病理损伤的程度密切相关。同时提示混合感染的BALB/c小鼠应答模式与Py17XL感染BALB/c小鼠的应答模式相同。
To investigate the relationship between characteristics of immune response and host pathological injury in BALB/c mice co-infected with Plasmodium yoelii 17XL （Py17XL） and Plasmodiurn chabaudi AS （PEAS）. Infections were initiated at the same time by intraperitoneal （i. p. ） injection of PylTXL, PcAS, or Py17XL＋ PeAS parasitized e- rythrocytes （PE） for each group of BALB/c mice. Parasitemia and mortality were monitored daily. Tail blood collected at different time points was anti-coagulated with heparin on days 3, 5, and 8 day post-infection （pi） and centrifuged briefly for DNA extraction using a High Pure Blood Genome DNA Extraction kit. Real time quantitative （RTQ） PCR was used to determine the parasite burden. On days 0, 1, 3, 5, 8, 10, 12, and 15 pi, splenocyte IFN-7 and IL-4 were dynamically detected with ELISA. Results showed that the level of IFN-γ in BALB/c mice infected with Py 17XL and mice with a mixed infection increased on days 3 and 5 pi, but the level of IFN-7 was three times higher on day 5 pi in mice infected with PcAS compared to other groups of mice. Moreover, the production of IL-4 in the mice infected with PylTXL and mice with a mixed infection peaked on day 8 pi （P〈0.01） and then slowly declined to a level higher than normal. In BALB/c mice infected with PEAS, the highest IL-4 level appeared on day 10 pi. BALB/c mice infected with PeAS devel- oped only moderate parasitemia that peaked on day 9 pi and then decreased gradually. All mice survived. However,Pyl7XL was lethal to BALB/c mice on day 5, with a peak parasitemia of 50.57± 9.12%. In contrast, mice infected with mixed species developed a dramatic peak parasitemia on day 5 pi, and all mice died on day 8/9 pi. QRT-PCR data revealed that PylTXL prevailed in BALB/c mice with mixed infections before they died on day 8 pi. These results indicate that pro- tective immunity against malaria infection depends on the establishment of effective Thl and Th2 responses and a successful switching of immune response from Thl to Th2. The mode of immune response was closely associated with the degree of pathological injury to the host. The mode of immune response mode in mice infected with Py 17XL was the same as that in mice with a mixed infection.
出处
《中国病原生物学杂志》
CSCD
北大核心
2013年第4期346-349,共4页
Journal of Pathogen Biology
基金
黑龙江省教育厅青年学术骨干支持计划项目(No.1155G55)
关键词
Py17XL和PcAS混合感染
免疫应答
病理损伤
Co-infected with Plasmodium yoelii 17XL and Plasmodium chabaudi AS
immune response
pathologicalinjury
