Receptor heterogeneity and invasion on erythrocytes by Plasmodium falciparum merozoites in Indian isolates.

Malarial parasites, P. falciparum with different capabilities of invasion on sialic acid deficient erythrocytes have been identified. All three parasite lines (FDL-RI; FSJ-B5; FJB-D2) required sialic acid for invasion. However, parasite FSJ-B5 cultured in neuraminidase treated erythrocytes invaded at 20% efficiency, whereas in the cells treated with neuraminidase and trypsin together, the parasites FDL-R1 and FJB-D2 invaded at less than 10% efficiency. It is therefore suggested that different parasites isolated from different geographical regions of India possess two receptors--one that binds at sialic acid dependent ligand and other that binds in sialic acid independent ligand as demonstrated by ELISA using monoclonals against glycophorin A and glycophorin B. The sialic acid independent ligand may be having different affinities of their receptors for the malarial parasites.