约氏疟原虫自然传播阻断的发生与原虫血症相关性的研究

STUDIES ON NATURAL TRANSMISSION-BLOCKING AND PARASITEMIA OF PLASMODIUM YOELII

目的 探讨约氏疟原虫感染早期自然传播阻断的发生机制。方法 观察小鼠红内期原虫血症水平、蚊体内有性阶段的虫体发育状况以及PRBC提取物对脾细胞产生NO的诱导作用。结果 当红细胞感染率达到 15 %～ 2 0 %这一阈值时 ,配子体对蚊的感染力明显减弱或丧失 ;PRBC提取物能够诱导脾细胞合成NO ,其诱导能力具有剂量依赖性。结论 疟原虫自然传播阻断的发生取决于红细胞感染率的高低和中间宿主体内免疫细胞活化后产生的NO水平。

Aim To clarify the mechanism of natural transmission-blocking during the early phase of infection with Plasmodium yoelii.Methods Observing the levels of parasitemia in mice,development of sexual stage parasites in mosquitoes and induced effect of PRBC extract on NO 2 -from supernatants of spleen cells.Results Infectivity of gametocytes to mosquitoes was dramatically decreased or lost when parasitemia ranged between 15 %and 20%;PRBC extract could induce NO production by spleen cells,which showed dose-dependent manner.Conclusion The occurring of natural transmission-blocking depends on the levels of parasitemia and NO production by the activated immune cells in intermediate host.