ABSTRACT
AIM:To cultivate the exoerythrocytic stage of Plasmodium yoelii in vitro and to study some involved affecting factors.METHOD:In vitro cultivation.RESULTS:The monolayer hepatocytes grown in 1 6 - mm plastic cell culture dishes were inoculated with sporozoite sus- pension prepared from Anopheles stephensi mosquitoes for48hours.At a final density of2? 1 0 4 cells per well,the infection rate of hepatocyte,cultured in medium supplemented wit15 % bovine serum,was 0 .0 35? 0 .0 1 3% ,the diameter of the nearly mature EEF of Plas- modium yoelii was up to40 .3? 31 .6 ?m,and contained more than1 0 0 nuclei,the number of EEF might be4- 1 0 /cm2 .An intraperitoneal inoculation of the EE schizonts to mice could induce parasitemia.At a final density of0 .5? 1 0 4 or4? 1 0 4 cells per well or the hepatocytes cultured in medium supplemented with1 0 % bovine serum,no EEF could be observed.CON- CL USION:The density of hepatocytes and culture medium are important for the cultivation of the EE stage of Plasmodium yoelii.This procedure will lay foundation for the further studies of the sporozoite invasion,the development of EEF and the affecting factors in- volved.