CD4^+CD25^+T细胞在夏氏疟原虫感染鼠中的应答差异

Characteristic of CD4^+CD25^+Regulatory T Cells Activation During Plasmodium chabaudi chabaudi Infection

为探讨CD4+CD25+调节性T细胞(Treg细胞)在夏氏疟原虫感染过程中的活化特点及其与疾病进展的相关性,用夏氏疟原虫分别感染BALB/c和DBA/2小鼠,Giemsa染色制备薄血膜,镜检计数红细胞感染率;以流式细胞术检测脾细胞悬液中Treg细胞百分含量;ELISA测定脾细胞培养上清IFN-γ水平。BALB/c小鼠原虫血症于感染后第8d达到峰值34.4%后迅速下降,于感染后第15d左右小鼠自愈;其IFN-γ水平和Treg细胞百分含量均在感染后第5d明显增加后开始下降(P<0.01);DBA/2小鼠原虫血症于感染后第9～11d一直维持在峰值38%左右,并在感染后约第10d小鼠死亡;其IFN-γ水平在感染后第3d明显升高后迅速回落(P<0.01),Treg细胞百分含量在感染后的前8d平稳升高,但于感染后第8～11d出现骤然上升。结果提示,CD4+CD25+调节性T细胞数量异常变化与宿主感染结局呈密切相关性。

In order to investigate characteristic of CD4^＋ CD25^＋ regulatory T cells （Tregs） activation and correlation with disease progression in BALB/c and DBA/2 mice infecled with Plasmodium chabaudi chabaudi AS （P. c. chabaudi AS）. Parasitemia was monitored by microscopic evaluation of thin blood films with Giemsa staining. Percentage of Tregs in total spleen CD4 ＋ T cell population in BALB/c and DBA/2 mice after inoculation was measured by flow cytometry, IFN-3, production was monitored by measuring the amount of IFN-3, in the splenocyte culture supernatant using ELISA kits. P. c. chabaudi AS infected BALB/c mice developed a moderate parasitemia with a peak 34.4% on the 8th day post inoculation （p. i. ） followed by a quickly drop and all mice survived on the 15th day p. i. In addition, in cultured splenocyted supernatant from BALB/c, both IFN-3, production and Tregs percentage increased significantly （P 〈0.01） on 5th day p.i. and then decreased However, P. c. chabaudi AS infected DBA/2 mice showed a parasitemia that maintained approximately 38% by 91th - 1 lth day and all mice died around the lOth day p. i. IFN-γ, production from splenocyte supernatant from DBA/2 ：increased significantly （P 〈0. 01 ） on the 3rd day p. i. and then dropped quickly. The percentage of Tregs from splenocyte supernatant from DBA/2 kept steady elevated level by the first 8 days after the infection, and appeared abruptly ascend on 8th - 11th day after the infection. The results indicated that the abnormal changes of CD4^ ＋ CD25^＋ regulatory T cell amount and the infection outcome of the host assume close reciprocity.