Activation of Lymphocytes in Healthy Neonates Within Hours of Birth.

It is now established that immune maturation occurs along a defined trajectory in the weeks and months after birth, but the immediate changes that occur within immune cells following birth is less clear. In this study, we monitored the immune profile of neonates via analysis of paired samples (n= 28) of cord blood and heel prick blood taken at varying times post term delivery by planned elective caesarean section. This paired approach accounted for the between-subject variability often observed over the first week of life. We identified rapid changes in immune cell populations within hours of birth. Specifically, we observed increased proliferation in effector T cells (but not regulatory T cells) that exhibited an increase in cytokine producing ability and also an increase in the percentage of CD3 T cells over this short time frame. This indicates that the mobilisation of the immune system is immediate post birth, presumably as a response to sudden exposure to the external environment, antigen or stress. Hence, immune development may start to occur more rapidly than previously proposed and as such, to study this trajectory, blood sampling should begin as soon after birth as possible.

NF-κB regulation in maternal immunity during normal and IUGR pregnancies.

Intrauterine Growth Restriction (IUGR) is a leading cause of perinatal death with no effective cure, affecting 5-10% pregnancies globally. Suppressed pro-inflammatory Th1/Th17 immunity is necessary for pregnancy success. However, in IUGR, the inflammatory response is enhanced and there is a limited understanding of the mechanisms that lead to this abnormality. Regulation of maternal T-cells during pregnancy is driven by Nuclear Factor Kappa B p65 (NF-κB p65), and we have previously shown that p65 degradation in maternal T-cells is induced by Fas activation. Placental exosomes expressing Fas ligand (FasL) have an immunomodulatory function during pregnancy. The aim of this study is to investigate the mechanism and source of NF-κB regulation required for successful pregnancy, and whether this is abrogated in IUGR. Using flow cytometry, we demonstrate that p65+ Th1/Th17 cells are reduced during normal pregnancy, but not during IUGR, and this phenotype is enforced when non-pregnant T-cells are cultured with normal maternal plasma. We also show that isolated exosomes from IUGR plasma have decreased FasL expression and are reduced in number compared to exosomes from normal pregnancies. In this study, we highlight a potential role for FasL+ exosomes to regulate NF-κB p65 in T-cells during pregnancy, and provide the first evidence that decreased exosome production may contribute to the dysregulation of p65 and inflammation underlying IUGR pathogenesis.

Inflammatory and Immune System Markers.

Since preeclampsia was first described by Hippocrates in 400 BC, the theory of its causation has shifted from toxins to a current theory that incorporates both vascular and immunological causation. Poor placentation whether it is genetically predisposed or due to low expression of defective HLA-G on fetal trophoblasts is believed to be the initial insult. Oxidative stress from placental ischemia/hypoxia leads to an overload of trophoblast debris by stimulating apoptosis or necrosis. Partial failure of the maternal immune system to tolerate the paternal alloantigens activates maternal immune cells to secrete cytokines whose pleiotropic functions lead to dysfunction of the maternal vascular and placental endothelium, blood coagulation, and fibrinolytic system. This chapter describes some of the key methodologies (flow cytometry, ELISAs, and multiplex immunoassays) for the identification and quantification of inflammation and immune system markers in the study of preeclampsia pathogenesis, as well as diagnostic and therapeutic development. The methodologies may be utilized for a variety of tissue sources in the study of preeclampsia: maternal peripheral blood, umbilical cord blood, intervillous blood, decidua, chorionic villous, amnion and chorion membranes, and cell culture supernatant.