In-Vitro Evaluation of Anti-Adhesion Activity by Antibodies to Pregnancy Malaria Vaccine Candidates

Malaria caused by Plasmodium falciparum continues to be a global problem with devastating consequences. Pregnancy malaria is associated with low birth weight, maternal anemia, and gestational hypertension, and both inflammation and the fetal response to infection may contribute to these poor outcomes. Pregnancy malaria is caused by P. falciparum-infected erythrocytes that bind to the placental receptor chondroitin sulfate A (CSA) and sequester in the placenta, where they cause disease and death for the mother and her offspring. Women become resistant to pregnancy malaria as they acquire antibodies that target surface proteins of placental parasites. Malaria vaccine candidates targeting the parasite s liver stage or blood stage may not protect pregnant women and their unborn children. The primary hypothesis in this study is that antibodies raised in animals against recombinant pregnancy malaria vaccine candidates will have a similar functional activity as naturally acquired antibodies. Up to 1500 pregnant women will be recruited into a cross sectional study that will be conducted in Rakai, Uganda. Women presenting for delivery and their newborns and women presenting for antenatal visit at Kalisizo Hospital, Rakai District will be enrolled. Samples collected from the women will be used in in-vitro assays to assess the functional activity of antisera raised against pregnancy malaria vaccine candidates as the primary outcome of this study. For our secondary outcomes, we will examine various factors that can lead to poor outcomes such as low birth weight of infants by measuring newborns for birth weight and physical and muscular maturity using the Dubowitz Ballard Exam for Gestational Age. We will also study the effects of intermittent preventive therapy during pregnancy (IPTp) on immune responses in the mother as well as the effect of HIV infection on the acquisition of immunity to pregnancy malaria. Clinical, parasitological and host response endpoints (including naturally acquired functional antibodies against CSA-binding parasites) will be analyzed using appropriate statistical methods, including adjustment for possible confounders, to determine factors associated with malaria infection and disease in pregnant women, as well as pregnancy outcomes.