ROLE OF THE PLASMODIUM-FALCIPARUM MATURE-PARASITE INFECTED ERYTHROCYTE SURFACE-ANTIGEN (MESA PFEMP-2) IN MALARIAL INFECTION OF ERYTHROCYTES/

During intraerythrocytic growth of Plasmodium falciparum, several para site proteins are transported from the parasite to the erythrocyte mem brane, where they bind to membrane skeletal proteins. Mature-parasite- infected erythrocyte surface antigen (MESA) has previously been shown to associate with host erythrocyte membrane skeletal protein 4.1. Usin g a spontaneous mutant of P falciparum that has lost the ability to sy nthesize MESA and 4.1-deficient erythrocytes, we examined growth of ME SA(+) and MESA(-) parasites in normal and 4.1-deficient erythrocytes. Viability of MESA(+) parasites was reduced in 4.1-deficient erythrocyt es as compared with that for normal erythrocytes, but MESA(-) parasite s grew equally well in 4.1-deficient and normal erythrocytes. Cytoadhe rence of MESA(+)- and MESA (-)-parasitized normal and 4.1-deficient er ythrocytes to C32 melanoma cells was similar, indicating that neither protein 4.1 nor MESA plays a major role in cytoadherence of infected e rythrocytes. Localization of MESA in normal and 4.1-deficient erythroc ytes was examined by confocal microscopy. MESA was diffusely distribut ed in the cytosol of 4.1-deficient erythrocytes but was membrane-assoc iated in normal erythrocytes. These findings suggest that MESA binding to protein 4.1 plays a major role in intraerythrocytic parasite viabi lity. (C) 1995 by The American Society of Hematology.