[In vitro cultivation of the exoerythrocytic stage of Plasmodium berghei].

This paper reports on an in vitro culture system for the exoerythrocytic (EE) stage of Plasmodium berghei (P.b.) using embryonic lung cells. The system was first developed by our laboratory in China. The embryonic lung cells were isolated by trypsin digestion of a human embryonic lung obtained from a therapeutic abortion case and was designated as cell line Elu 8801. Anopheles stephensi mosquitoes were infected by biting P.b. ANKA strain infected Kunming mice and after 18-21 days were dissected under aseptic conditions for preparation of a sporozoite suspension. This suspension was used to inoculate the monolayer cultures of Elu 8801. Regular examination found that following a cultivation for 48 hours, up to 100 multinuclear EE schizonts of P.b. could be observed on 1 x 1 cm cover slide. Seventy-two hours later mature merozoites were seen among part of the schizonts. An intraperitoneal inoculation of the supernatant culture medium to mice could induce malaria infection which could be transferred to other mice by blood inoculation. When the mice infected with the second generation were allowed to feed A. stephensi, sporozoites developed in the mosquitoes. The results demonstrate that the human embryonic lung cell line Elu 8801 established in our laboratory is susceptible to P.b. ANKA sporozoites and can support the developmental maturation of EE stages, producing potentially infectious merozoites.