Immune response characteristics in BALB/c mice infected with different plasmodia were investigated.BALB/c mice were infected by intraperitoneal injection with 1 × 106 virulent P. yoelii 17XL or P. chabaudi AS parasitized erythrocytes, Splenocyte IFN-γ and IL-4 producing levels were measured by dynamic ELISA. The apoptosis of CD4+T cell was detected by flow cytometry. The results showed that during early stage of P. y 17XL infection, the parasitaemia of mice continuously increased and the secretion levels of IFN-γ and IL-4 appeared a transient significant increment only on d3 post-infection, though with low peak value; and a large number of CD4 + T cells of spleen went apoptosis, and all mice died. However, the increment of parasitemia of mice infected with P. c AS was slow and the levels of IFN-γ reached to peak value on d5 post-infection, and IL-4 on dl0 post-infection; And the time of peak value was maintained fairly long; a significant increment of the CD4 +T cells of spleen apoptosis appeared d8 post-infection, and all mice survived. Therefore, protective immunity against malaria infection depended on the establishment of effective Th1 and Th2 responses and coordinative transition. The time phase and quantity of CD4 + T apoptosis during the early infection might be a reason that affected the immune response strength and/or caused the immune of the host to inhibit, thereby affected the outcome of the host to infect the plasmodia.%探讨不同疟原虫感染BALB/c小鼠的免疫应答特点.BALB/c小鼠经腹腔注射致死型约氏疟原虫(P.y17XL)和夏氏疟原虫(P.c As)感染的红细胞,计数红细胞感染率;ELISA动态检测感染小鼠脾细胞培养上清中IFN-γ和IL-4水平;流式细胞术检测脾中CD4+T细胞凋亡数量.约氏疟原虫(P.y17XL)感染早期,小鼠原虫血症持续上升;IFN-γ和IL-4分泌水平仅在感染后第3天出现一过性有意义的升高,而且峰值较低;脾中CD4+T细胞大量凋亡,小鼠全部死亡;而夏氏疟原虫(P.c AS)感染小鼠,原虫血症上升缓慢;IFN-γ分泌水平在感染后第5天达峰值;IL-4分泌水平在感染后第10天达峰值,且峰值较高维持时间较长;脾中CD4+T细胞凋亡细胞于感染后8 d出现有意义升高,小鼠全部存活.抗疟保护性免疫有赖于Th1和Th2型免疫应答的有效建立和协调过渡,感染期间CD4+T细胞凋亡的时相和数量可能是影响免疫应答的强度或引起宿主免疫押制的因为,从而影响宿主疟原虫感染的结局.
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