夏氏疟原虫感染过程中调节性B细胞的表达变化

Expression Changes of Regulatory B cells during Plasmodium chabaudi Infection

调节性B细胞(regulatory B cells,Bregs)是近年来发现的通过分泌IL-10发挥免疫调节作用的B细胞,其在疟疾免疫应答中的作用尚不清楚。利用血液阶段夏氏疟原虫(Plasmodium chabaudi AS,P.c AS)感染的BALB/c小鼠,观察了感染过程中Bregs数量变化及其表面分子表达情况。结果显示,BALB/c小鼠感染P.c AS后红细胞感染率逐渐升高,于感染后第9天达到30%,多数小鼠死亡。脾组织细胞因子IL-10 mRNA水平在感染后显著升高,感染后第5天达到高峰,感染后第8天仍为正常小鼠的10倍左右。CD4+细胞中IL-10+细胞百分比和绝对数量在感染后第5天达到峰值,于感染后第8天回落至正常水平;而CD19+细胞中IL-10+细胞(Bregs)百分比在感染后持续上升,在感染后第8天达到CD19+细胞的5%左右;感染后第5天,脾中CD4+IL-10+细胞绝对数量高于CD19+IL-10+细胞,至感染后第8天,CD19+IL-10+细胞绝对数量显著高于CD4+IL-10+细胞(P﹤0.01),约90%Bregs为CD5-细胞。结果提示,P.c AS感染过程中Bregs显著活化,是感染1周后IL-10的主要产生细胞。

Regulatory B cells（Bregs） are a newly discovered B cell subset which regulates immune response by secreting interleukin-10（IL-10）,however,the role of its immune response against malaria remained unclear.The study adopted infected BALB /c mice with blood-stage Plasmodium chabaudi AS（P.c AS） involvement of Bregs in the immune response against Plasmodium chabaudi and observed the number changes of Bregs during the infection and the expression of their surface molecules.The results showed that after the mice infected with P.c.AS the infection rate of red blood cells gradually increased,and 9 days p.i.it reached to 30%,most of the mice died.The level of spleen tissue cytokine IL-10mRNA remarkably increased after the infection and reached to the peak at day 5,8 days p.i.it still was 10 folds of normal mice.The percentage and absolute number of IL-10＋reached to the peak d5 p.i.and fell back to normal at d8 p.i.While the proportion of IL-10＋cells in CD19＋cells kept rising after the infection and reached about 5% of CD19＋cells at d8 p.i..Whereas the absolute number of CD4＋IL-10＋cells in spleen was higher than CD19＋IL-10＋;until d8 p.i.the absolute number CD19＋IL-10＋cells remarkably higher than CD4＋IL-10＋cells（P 0.01）,about 90% Bregs at was CD5-cells.The results suggested that during the process of P.c AS infection Bregs significantly activated and they were the major producing cells of IL-10 a week after infection.