Adherence of <i>Plasmodium falciparum</i> to Chondroitin Sulfate A in the Human Placenta

TLDR

Women are especially vulnerable to malaria in their first and second pregnancies despite long‑term exposure in endemic regions. The study isolated infected red blood cells from human placentas to examine their binding properties. The placental infected red blood cells bound specifically to chondroitin sulfate A, not to other extracellular matrix proteins or receptors, and this adhesion—mirroring the distribution seen in naturally infected placentas and competitively blocked by CSA—indicates that CSA binding selects a parasite subpopulation responsible for maternal malaria.

Abstract

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