Plasmodium falciparum: a family of sulphated glycoconjugates disrupts erythrocyte rosettes.

The ability of Plasmodium falciparum-infected erythrocytes to form spontaneous rosettes with uninfected red cells is a parasite adhesion property which has been associated with severe malaria. The mechanism of rosetting remains unknown, but the ability of heparin to disrupt rosettes has been recognised previously. In this paper we show that a group of sulphated glycoconjugates including sulphatide, dextran sulphate, and fucoidan are more effective rosette reversing agents than heparin and are active against both laboratory strains and wild isolates. Other related anionic glycosaminoglycans such as the chondroitin sulphates A, B, and C and hyaluronic acid have no effect on rosette formation. This family of sulphated glycoconjugates which are active against rosettes is also known to inhibit sporozoite invasion of hepatocytes and merozoite reinvasion of erythrocytes, suggesting that sulphated glycoconjugate interaction may be an important process in cell adhesion at different stages in the plasmodial life cycle.