Toll样受体在约氏疟原虫感染早期树突状细胞应答中的作用地位

目的探讨致死型约氏疟原虫(Plasmodium yoelii17XL,P.y17XL)感染早期,Toll样受体(Toll like receptor,TLR)在树突状细胞(dendritic cells,DCs)活化中的作用地位。方法用P.y17XL感染易感的BALB/c和抵抗的DBA/2小鼠,计数红细胞感染率;制备感染前和感染后第3d、5d小鼠脾细胞悬液,采用流式细胞分析技术检测两种小鼠感染不同时间脾细胞悬液中细胞内表达TLR9(Toll like receptor 9,TLR9)的DCs和细胞表面表达TLR4(Toll like receptor 4,TLR4)的DCs的百分含量。结果两种小鼠脾DCs细胞内TLR9的表达水平均于感染后第3d开始明显升高(P<0.01),在第5d达到最高水平(P<0.01),但两种小鼠相比无统计学意义。同时,两种小鼠DCs表面TLR4的表达水平均未见明显变化。结论在P.y17XL感染早期,TLR9可能是介导DCs活化的模式识别受体。

Role of Toll-like receptor in the dendritic cell response during early Plasmodium yoelii infection

To investigate the role of Toll like receptor （TLR） in the activation of dendritic cells （DC） during early Plasmodiurn yoelii infection of the lethal strain 17XL （P. y 17XL）, susceptible BALB/c and resistant DBA/2 mice were infected by i. p. injection of the P. y 17XL-parasitized erythrocytes, and the parasitemia of individual mice was monitored by the microscopic examination of blood smear stained with Giemsa. Mice from normal and infected groups were sacrificed on 0,3 and 5 days postinfection to collect their spleen cells. And the expressions of TLR-9 and TLR-4 on the cell surface of DCs in spenonocytes of these two strains of mice were assayed by applying flow cytometry to quantitatively analyze the percentages of CD11c^＋ TLR9^＋ DCs and CD11c^＋ TLR4^＋ DCs. It was found that the population of CD11c^＋ DCs expressing TLR9 was significantly increased on day 3 and peaked on 5 p.i. in BALB/c （P〈0.01） and DBA/2 mice（P〈0.01）. However, there was no statistical significance between these two strains of mice. Meanwhile, there was no change on the population of CD11c^＋ DCs expressing TLR4 in BALB/c and DBA/2 mice. These results indicate that TLR9 may contribute to the DC activation during early stages of P. y17XL infection.