Maintenance of healthy pregnancy is reliant on successful balance between the fetal and maternal immune systems. Although maternal mechanisms responsible have been well studied, those used by the fetal immune system remain poorly understood. Using suspension mass cytometry and various imaging modalities, we report a complex immune system within the mid-gestation (17-23 weeks) human placental villi (PV). Consistent with recent reports in other fetal organs, T cells with memory phenotypes, though rare in abundance, were detected within the PV tissue and vasculature. Moreover, we determined T cells isolated from PV samples may be more proliferative than adult T cells at baseline after T cell receptor (TCR) stimulation. Collectively, we identified multiple subtypes of fetal immune cells within the PV and specifically highlight the enhanced proliferative capacity of fetal PV T cells.

This content is only available via PDF.

Article PDF first page preview

Article PDF first page preview