Biological activities of antigen presenting cells in normal and preeclampsia pregnancy

Abstract

Background Pregnancy uniquely sustains the fetal allograft within the mother, an antigenically dissimilar host. The mechanisms involved in nature's successful transplantation are poorly understood, but involve multiple cellular and humoral immune mediators. Insights into early pregnancy development at the maternal-fetal interface of the implanting blastocyst nominates antigen presenting cells (APCs) for key roles in the immune responses of successful pregnancies. Little is known about the role of immune cell function in the human basal plate, a key maternal fetal interface, in the last trimester of uncomplicated pregnancies. Even less is known about immune cell dysregulation in the basal plate of pregnancies complicated by preeclampsia, at term or preterm. The Aims of this grant fill this gap in knowledge. Preeclampsia-PE (defined as hypertension and proteinuria or organ dysfunction, in pregnant women over 20 weeks of gestation) is one of the most important causes of maternal and perinatal morbidity and mortality around the world, especially in developing countries. Its pathogenesis is not completely elucidated, with marked influence of immune factors. Aim To elucidate the localization, frequency and to characterize the responses of basal plate APCs of uncomplicated third trimester pregnancies and pregnancies complicated by preeclampsia. Materials and methods/Results Case-control design, with 15 subjects in each group (uncomplicated versus PE), adjusted for type of delivery (vaginal vs cesarean) and gestational age; conducted within the Washington University Medical School. Clinical and demographic data will be collected. Placenta basal plates will undergo systematic random sampling, micrography and immunohistochemistry (IHC) with the antibodies: DC-SIGN+ (dendritic cells), CD68+ (macrophages), DC-LAMP (mature dendritic cells/macrophages), and DEC-205 (homologue of mannose receptor in maturing macrophages) followed by hematoxylin counterstaining of nuclei. Morphometric (quantitative) approaches will be used, to determine the frequency of cells positive with each of these markers and the frequency and size of spiral arterioles. Considering APC characterization and responses we will isolate CD14+ cells from both groups noted above, determine the ratio of CD14+MHCIIint and CD14+MHCIIhigh cells. We will use FACS to sort the cells and stimulate the two classes in vitro with TLR agonists. We will collect supernatants and determine concentration of IL-10, IL-6, TNF-±, IL-12, IL-23 and nitric oxide (NO). We will measure levels of inhibitory receptors, with specific attention to ILTs and PD1L. We will also assess MHC class I expression, noting in particular, HLA-G expression. From selected donors we will also perform global gene expression profiling. The differences of the gross features of the placentas analyzed, morphometric analyses, and assays of cytokines expression be done by ANOVA with Tukey's post hoc test for multiple comparisons. (AU)