Abstract:

The persistent in vitro cultivation of ethrythrocytic-stage Plasmodium yoelii has not come to successful results. In this study, we modified the cultivation based on Trager’s method. The modifications included: placing P. yoelii parasites in a small chamber of a suspension system, and agitating them into suspension by a magnetic stirrer; daily replacement of the culture medium and addition of new reticulocytes into the medium; and cultivation at 37 ℃ with 5% CO2. The in vitro cultures were injected daily into mice through tail vein, and the infection status in mice was examined on day 3. Results showed that the proportion of red blood cells with parasite infection increased to 2.200% within 24 h of in vitro cultivation, then decreased till 0% on day 10. As to the mouse model, the mice all showed positive infection from days 1 to 9, with highest rate on day 1 (54.960%), and no infection on day 10. This result suggested that the cultivation of erythrocytic-stage P. yoelii can be maintained up to 9 days in vitro without losing infectivity.
 

Key words: Plasmodium yoelii, Ethrythrocytic stage, Culture, In vitro