Expression of variant surface antigens by Plasmodium falciparum parasites in the peripheral blood of clinically immune pregnant women indicates ongoing placental infection

Placenta-sequestered Plasmodium falciparum parasites that cause pregnancy-associated malaria (PAM) in otherwise clinically immune women express distinct variant surface antigens (VSA(PAM)) not expressed by parasites in nonpregnant individuals. We report here that parasites from the peripheral blood of clinically immune pregnant women also express VSA(PAM), making them a convenient source of VSA(PAM) expressors for PAM vaccine research.