Human monoclonal IgG selection ofPlasmodium falciparumfor the expression of placental malaria-specific variant surface antigens

Abstract

Pregnancy-associated Plasmodium falciparum malaria (PAM) is a major cause of morbidity and mortality in African women and their offspring. PAM is characterized by accumulation of infected erythrocytes (IEs) that adhere to chondroitin sulphate A (CSA) in the placental intervillous space. We show here that human monoclonal IgG antibodies with specificity for variant surface antigens (VSA) specifically expressed by CSA-adhering IEs (VSA_PAM) can be used in vitro to select parasites from nonpregnant donors to express VSA_PAM and that this selection for VSA_PAM expression results in preferential transcription of var2csa. The results corroborate current efforts to develop PAM-specific vaccines based on VAR2CSA.