ADHERENCE OF PLASMODIUM-FALCIPARUM TO CHONDROITIN SULFATE-A IN THE HUMAN PLACENTA

Women are particularly susceptible to malaria during first and second pregnancies, even though they may have developed immunity over years o f residence in endemic areas. Plasmodium falciparum-infected red blood cells (IRBCs) were obtained from human placentas. These IRBCs bound t o purified chondroitin sulfate A (CSA) but not to other extracellular matrix proteins or to other known IRBC receptors. IRBCs from nonpregna nt donors did not bind to CSA. Placental IRBCs adhered to sections of fresh-frozen human placenta with an anatomic distribution similar to t hat of naturally infected placentas, and this adhesion was competitive ly inhibited by purified CSA. Thus, adhesion to CSA appears to select for a subpopulation of parasites that causes maternal malaria.