Category: Reproductive immunology
In healthy pregnancies, labor is marked by the well-defined transition to an inflammatory state in reproductive tissues. It has been postulated that this increase in inflammation is the result of maternal loss of tolerance towards the fetus. However, recent work has discovered central memory T cells in cord blood of preterm but not term infants that are capable of secreting cytokines in response to maternal antigens suggesting that they might play a role in initiating preterm labor. To address directly if fetal T cells can be found at the fetal-maternal interface that might contribute to the initiation of parturition, we performed deep immunophenotyping and functional analysis of cells present at the feto-maternal interface. Using mass cytometry (CyTOF) this study has identified diverse T cell populations in the fetal derived tissues (placental villi and fetal membranes), including effector, central and tissue resident memory T cells in the second trimester (17-23 weeks’ gestation) and at full term (38-40 weeks’ gestation) of healthy pregnancies. Furthermore, upon stimulation with lysed maternal (decidual) components from the same pregnancy, fetal T cells secrete TNFα but don’t secrete TNFα when stimulated with third party PBMCs. This result suggests fetal T cells within placental villi respond to antigens present on the maternal side of the interface, but not to blood antigens from unrelated donors. Collectively these findings illustrate a dynamic and functional arsenal of T cells within fetal tissues as early as the second trimester and insinuate that fetal T cells may contribute to inflammation seen during labor.
Jessica Toothaker– Graduate Student, University of Pittsburgh
Collin McCourt– UPMC Childrens Hospital of Pittsburgh
Stephanie Stras– UPMC Childrens Hospital of Pittsburgh
Oluwabunmi Olaloye– UPMC Childrens Hospital of Pittsburgh
Liza Konnikova– Assistant Professor, UPMC Childrens Hospital of Pittsburgh