Structural aspects of Plasmodium relevant to vaccination against malaria

The extracellular stages of Plasmodium which can be inactivated with antibodies include the sporozoites, merozoites and microgametes. The surface of sporozoites and merozoites are known to bind antibodies which render them unable to invade host cells. Intra-erythrocytic merozoites, trophozoites and schizonts release antigens which are conveyed to the surface of the host cell, although they do not appear to be attacked by antibodies directly. The significance of these observations is discussed.