Plasmodium falciparum merozoite adhesion is mediated by sialic acid

The invasion of host red blood cells by Plasmodium falciparum merozoites is a complex process requiring multiple receptor-ligand interactions. Glycophorin A, a sialic acid-rich integral membrane protein, is an important RBC receptor for merozoites. We stably expressed glycophorin A in wild type Chinese hamster ovary (CHO) cells and in Lec 2 CHO cells which have a defect in the ability to sialylate proteins. Malaria merozoites were assessed for the ability to adhere to CHO cells that were either untransfected or expressed recombinant glycophorin A. Merozoites only adhered to wild type CHO cells and they did so irrespective of the expression of glycophorin A. These results suggest that cellular adhesion, the earliest event in the malaria invasion process, is mediated by sialic acid residues. This model system will provide valuable molecular information regarding early events in the malaria invasion process.