Antigenic differences and conservation among placental Plasmodium falciparum-infected erythrocytes and acquisition of variant-specific and cross-reactive antibodies.

Background. Pregnant women are infected by Plasmodium falciparum with novel antigenic phenotypes that adhere to chondroitin sulfate A (CSA) and other receptors in the placenta. The diverse and variant parasite protein P.

Cross-reactive surface epitopes on chondroitin sulfate A-adherent Plasmodium falciparum-infected erythrocytes are associated with transcription of var2csa.

Malaria in pregnancy is associated with placental accumulation of Plasmodium falciparum-infected erythrocytes (IE) that adhere to chondroitin sulfate A (CSA). Adhesion is mediated by P. falciparum erythrocyte membrane protein 1 (PfEMP1), a variant parasite protein expressed on the surface of IE and encoded by var genes.

Antibodies to variant surface antigens of Plasmodium falciparum-infected erythrocytes and adhesion inhibitory antibodies are associated with placental malaria and have overlapping and distinct targets.

We measured antibodies to chondroitin sulfate A (CSA)-binding and placental Plasmodium falciparum-infected red blood cells (PRBCs) among pregnant women with or without placental malaria. Immunoglobulin G to PRBC surface antigens was rare in uninfected primigravidae (3.7%), more prevalent in infected primigravidae (70%; P<.