IDENTIFICATION OF PERIPHERAL MEMBRANE-PROTEINS ASSOCIATED WITH THE TUBO-VESICULAR NETWORK OF PLASMODIUM-FALCIPARUM-INFECTED ERYTHROCYTES

During intracellular development of the malarial parasite numerous mem branous vesicles appear in the infected erythrocyte cytoplasm between the parasitophorous vacuolar membrane (PVM) and the erythrocyte plasma membrane. In this study we describe the characterization of a monoclo nal antibody which recognizes two major parasite-encoded proteins of 5 0 and 41 kDa. Immunofluorescence and immunoelectron microscopy demonst rated that the monoclonal antibody reacts with cytoplasmic vesicles of Plasmodium falciparum infected erythrocyte referred to as Maurer's cl efts. The antigens recognized by the monoclonal antibody were expresse d very early during the erythrocytic life cycle of the parasite, and r emained tightly associated within membrane vesicles even after merozoi tes are released from infected erythrocytes. The antigens were partial ly soluble in non-ionic detergents, and were released from the membran e by alkali treatment, indicating that the proteins recognized by the monoclonal antibody are peripheral membrane proteins. It is proposed t hat the 50 and 41 kDa antigens might be part of an underlying membrane skeletal network that provides structural support to vesicles and tub ules present in the infected erythrocyte cytoplasm. (C) 1998 Elsevier Science B.V. All rights reserved.