Sporogonic development of a malaria parasite in vitro.

The sporogonic cycle of the avian malaria parasite Plasmodium gallinaceum was completed in vitro. Ookinetes (motile zygotes) were seeded onto a murine basement membrane-like gel (Matrigel) in coculture with Drosophila melanogaster cells (Schneider's L2). Transformation into oocysts as well as subsequent growth and differentiation were observed in parasites attached to Matrigel and depended on the presence of L2 cells. Sporozoites were first observed on day 10 in culture. Specific circumsporozoite protein antigenicity was identified in mature oocysts and in sporozoites. It is now possible to follow the entire life cycle of Plasmodium in vitro.