Effect of irradiation on Plasmodium sporozoites depends on the species of hepatocyte infected.

The use of models such as rodents immunized with irradiated rodent malaria sporozoites can be helpful in defining the hepatic antigens which elicit a protective response. After "normal" penetration into the hepatocyte, and "normal" transformation, into trophozoites, irradiated sporozoites are known to begin development, but abort after a period of time that depends on the dose of radiation received. Experiments performed with cultured rat, mouse and Thamnomys gazellae hepatocytes infected with Plasmodium yoelii sporozoites demonstrated that the amount of radiation necessary to totally block the passage from the uninuclear to the multinuclear form differs for each species of hepatocyte. These results underline the problem posed by the models used in malaria research.