约氏疟原虫感染小鼠的巨噬细胞表面吞噬相关分子的研究

RESEARCH OF SURFACE MOLECULES RELATED MACROPHAGE PHAGOCYTOSIS FROM PLASMODIUM YOELII INFECTED DBA/2 MICE

为探讨致死型约氏疟原虫(Plasmodium yoelii 17XL)感染抵抗型DBA/2小鼠的脾巨噬细胞发挥吞噬功能的作用机制,本试验利用Giemsa薄血膜染色,光学显微镜计数红细胞感染率,观察巨噬细胞的吞噬功能;采用酶联免疫吸附法(ELISA)检测小鼠血清中抗P.y.17XL特异性IgG抗体水平;采用流式细胞技术(FACS)动态检测脾巨噬细胞表面膜分子CD36、CD64表达水平。结果表明,DBA/2小鼠红细胞感染率于感染后第7天高达31.87%,约第15天自愈;感染小鼠脾巨噬细胞吞噬能力于感染后第5天开始增强,至第10天吞噬率高达95%,随后维持于高水平;巨噬细胞表面分子CD36于感染后第3天开始升高,至第10天达到峰值;CD64表达水平于感染后第5天开始升高,随后持续维持于高水平;小鼠血清中抗P.y.17XL特异性IgG抗体水平在感染后第10天开始出现有意义的升高。结果显示,在P.y.17XL感染过程中,巨噬细胞通过表面分子CD36和CD64分别介导的非调理性和调理性吞噬方式杀伤疟原虫,提示巨噬细胞是DBA/2小鼠发挥抗疟保护性免疫的重要效应细胞。

To investigate the mechanism of splenic macrophages phagocytosis from resistant DBA/2 mice infected lethal strain Plasmodium yoelii （ P. y. 17XL）, erythrocyte infection rate was monitored through Giemsa-stained blood smears from tail blood by light microscope; antiparasite IgG antibody responses were also determined in sera of P. y. 17XL infected DBA/2 mice by ELISA in different time during infection; flow cytometry was used to quantitatively analyze splenic macrophages and the expression of CD36 and CD64 on splenic macrophages; and phagocytosis of macrophages was also observed. Results showed that primary parasitemia in vein blood was developed on day 2^nd post infection, which peaked with a level of 31.48% on day 7^th post infection, most mice cleared the infection and survived 15^th day post infection; rate of macrophage phagocytosis increased on day 5^th , which reached 95 % on day 10^th , then continued to remain high level ; the level of CD36 increased on day 3^rd which peaked on day 10^th, CD64 increased on day 5th then continued to remain high in DBA/2 mice, and IgG increased on day 10^th . It suggested that during P. y. 17XL infection, macrophage may play opsonic phagocytosis and opsonin-independent phagocytosis effect to inhibite parasitemia and kill plasmodium parasites via CD64 and CD36. And macrophages, as one of the most important cells, play a protective roles in the resistance of DBA/2 mouse to the early stage infection of P. y. 17XL.