Assay of erythrocyte components as inhibitors of Plasmodium falciparum merozoite invasion of erythrocytes.

Three red blood cell membrane fractions (Band 3, macromolecules exhibiting I antigenic determinants, and a delipidated glycoprotein fraction) were separated from red blood cell membranes and tested for their ability to inhibit penetration of red blood cells by Plasmodium falciparum merozoites in an in vitro inhibition assay. The delipidated glycoprotein fraction (containing the major sialoglycoproteins and devoid of Band 3) was the only fraction that inhibited merozoite invasion. This fraction showed 73% and 70% inhibition at 1 mg/ml and 500 micrograms/ml, respectively, and slight inhibition below these levels.