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Human Placenta Harbors a Diverse Immune Landscape With Inflammatory Potential
55 Pages Posted: 29 Apr 2020 Publication Status: Review Complete
More...Abstract
Throughout pregnancy, the maternal immunity is tolerant to the developing fetus. However, recent work suggests that the fetal immune system in utero is highly developed and may also contribute to tolerance. We hypothesized that each layer (maternal decidua, fetal membranes, and fetal villi) of the second trimester (ST) placenta harbors a distinct immune landscape. Mass cytometry of 11 ST placentas demonstrated that each tissue did have a unique immune profile. Specifically, the villi contain chemokine receptor (CCR)lo innate cells and enrichment of macrophages and DCs. In contrast, the decidua’s innate cells were CCRhi with abundant NK cells. Random forest classification accurately assigned samples as villi or decidua based on three distinct populations. Memory CD8 T cells were the dominant adaptive cells in all three layers and were more activated in decidua than villi. However, T cells within the villi could secrete TNFα/IFNγ when stimulated with maternal components, suggesting that villi T cells become proinflammatory upon exposure to maternal antigens. Furthermore, T cells from preterm villi had more activation transcripts than ST and term villi. Collectively, these findings illustrate a complex arsenal of immune cells within the placenta in utero and suggest that fetal T cells may contribute to preterm pathology.
Keywords: placental immunityfetal
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