Maternal microchimerism (MMc) is the transfer of maternal cells to the fetus across the placenta during pregnancy. MMc is found in both normal and abnormal pregnancies. The Harrington lab has previously shown that the amount of MMc increases with Plasmodium falciparum infections during pregnancies. In the same cohort, children with detectable levels of MMc were more likely to become infected with malaria but interestingly less likely to experience symptoms, suggesting that these maternal cells may regulate or educate the infant immune response against malaria. I aim to assess whether maternal cells selectively proliferate in the infant during the first infection with Plasmodium falciparum in order to mount an immune response by comparing the levels of MMc throughout three time points. To investigate the role of maternal cells in the infant immune response, I will test blood samples of infants exposed to placental malaria from three time points (a cord blood sample, a blood sample immediately preceding the infant’s first parasitemia, and a blood sample immediately following the infant’s first parasitemia) for the presence and amount of MMc. I hypothesize that MMc will be found in higher quantities in blood samples following an infant’s first infection with parasitemia, indicating that maternal cells help mount an immune response in the infant. Blood samples stored as dried blood spots (DBS) have been received from Ugandan field sites. First, the DNA was extracted from DBS samples. After comparison of class II HLA markers between a mom and her offspring, quantitative PCR (qPCR) will be used to target a unique, maternal HLA-class II marker in order to quantify MMc levels. The levels of MMc will be compared across the three time points. The results of my research have important implications for the current understanding of how MMc regulates the infant immune system.

In recent years, numerous studies have investigated the transfer of rare cells between a mother and her fetus during pregnancy, a phenomenon known as microchimerism. Maternal microchimerism (MMc) refers to maternal cells transferred to the fetus, whereas fetal microchimerism (FMc) refers to fetal cells transferred to the mother. FMc is found in both normal and abnormal pregnancies, and in particular is increased in settings of placental dysfunction such as pre-eclampsia. Plasmodium falciparum infection during pregnancy may lead to sequestration of infected erythrocytes in the placenta, known as placental malaria, that results in a phenotype similar to pre-eclampsia. The Harrington lab previously found that the fetus acquires more MMc in the setting of placental malaria. My research project investigates the reciprocal transfer of FMc to the mother in this setting. I hypothesize that malaria infection during pregnancy is associated with an increased prevalence of FMc. To complete this project, high-quality genomic DNA was extracted from samples gathered from a cohort of women in Mali. These samples came from women both with and without malaria infection during their pregnancy. After collecting the DNA, HLA-typing between a mother and her offspring were compared to determine a unique marker of fetal DNA. I am currently using quantitative PCR to amplify fetal alleles in the background of the mother in order to quantify FMc. Lastly, I will compare the level of assessed FMc in malaria exposed and non-exposed women. The findings from this research project have the potential to contribute important information about the complex role of microchimerism in immune function.