Immunoelectron microscopic localization of circumsporozoite antigen in the differentiating exoerythrocytic trophozoite of Plasmodium berghei.

The distribution of the circumsporozoite (CS) antigens in the 24 hour exoerythrocytic trophozoite of P. berghei was studied using Lowicryl immunogold electron microscopy. These antigens were present on the plasmalemma of the parasite, in disrupted areas of the host cell cytoplasm adjacent to the trophozoite and around inclusions of the host cell cytoplasm. There was evidence of a redistribution of the CS antigens away from the pellicular region of the sporozoite.