Plasmodium falciparum full life cycle and Plasmodium ovale liver stages in humanized mice

Experimental studies of Plasmodium parasites that infect humans are restricted by their host specificity. Humanized mice offer a means to overcome this and further provide the opportunity to observe the parasites in vivo . Here we improve on previous protocols to achieve efficient double engraftment of TK-NOG mice by human primary hepatocytes and red blood cells. Thus, we obtain the complete hepatic development of P. falciparum , the transition to the erythrocytic stages, their subsequent multiplication, and the appearance of mature gametocytes over an extended period of observation. Furthermore, using sporozoites derived from two P. ovale -infected patients, we show that human hepatocytes engrafted in TK-NOG mice sustain maturation of the liver stages, and the presence of late-developing schizonts indicate the eventual activation of quiescent parasites. Thus, TK-NOG mice are highly suited for in vivo observations on the Plasmodium species of humans. Mice engrafted with human cells are useful models for research on human malaria parasites. Here the authors show that the complete life cycle of Plasmodium falciparum and the liver stages of Plasmodium ovale can be studied in mice doubly engrafted with human primary hepatocytes and red blood cells.