Human monoclonal IgG selection of Plasmodium falciparum for the expression of placental malaria-specific variant surface antigens

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.