Surface antigens of Plasmodium falciparum-infected erythrocytes as immune targets and malaria vaccine candidates
Plasmodium falciparum-parasitized red cells attach to endothelial cells through several receptor-adhesin pairs. One of the adhesins on the surface of malaria-infected red blood cell is the modified band 3 molecule. We tested a synthetic peptide (HPLQKTY) based on a peptidic sequence of human band 3 protein to determine whether CD36 or thrombospondin is a receptor for the band 3-related adhesin. Although both CD36 and thrombospondin can bind parasitized cells independently, the HPLQKTY peptide and a monoclonal antibody (3H3) that recognizes the HPLQKTY sequence blocked only the adhesion of parasitized red cells to thrombospondin. The binding of thrombospondin, but not CD36, to the immobilized multiple antigen peptide-conjugated HPLQKTY was dependent on the concentration of the immobilized peptide. It would appear therefore, that thrombospondin is a receptor for the band 3-related cytoadhesion of parasitized erythrocytes.