Natural Microbial exposure populates the maternal fetal interface with diverse T cells.

scRNAseq was used to investigate how maternal microbial burden influences the immunology of the maternal fetal interface (MFI). Female mice werre cohoused with pet store mice for >4 weeks prior to conception and throughout gestation to naturalize maternal immunity. Cohoused dams were compared to specific pathogen free (SPF) control dams. Anti-CD45.2 IV labeling techniques were used to delineate immune cells in tissues from those in contact with circulation. IV labeling also permitted enrichment of placental (IV+) and decidal (IV-) tissue associated immune cells postprocessing. This is the first scRNAseq dataset to compare the immune cell populations from the MFI (combined placental and decidual tissue) of SPF and 'dirty' (pet store cohoused) dams. These data revealed significant changes to the immune cell composition and expansion of populations of T cells that phenocopy those described in the human decidua. Female C57BL/6 mice were cohoused with pet store mice for >4 wks prior to breeding. 14.5 days post conception cohoused and specific pathogen free (SPF) control dams were injected with a bolus of anti-CD45.2 antibody to label circulating immune cells. Dams were then euthanized and the maternal fetal interface (combined placenta and decidua) were harevsted, stained, and IV+ and IV- cells were sorted flow cytometrically and used to make single cell RNA sequencing libraries with the 10X Chromium platform. Onl;y primary syngeneic pregnancies were used in this dataset.