NK cells in the female reproductive tract (FRT) acquire an effector transcriptional program during menstruation

To evaluate the impact of the menstrual cycle on the transcriptional programs of NK cells in the female reproductive tract (FRT), we compared NK cells (Live lymphocytes, CD45.2+, DX5+, NK1.1+, Ly6G-, CD3-, CD19-) from the spleen and FRT of female C57BL/6J mice either treated with medroxy-progesterone acetate (MPA) or on day 8 of the pseudopregnancy / menstruation protocol. Prior to euthanasia, mice were injected intravenously with anti-CD45 antibody to discern between tissue and circulating NK cells in the FRT, with only tissue-resident cells sorted for analysis. Sorted splenic NK cells were not separated based on CD45 staining. The results indicate that FRT NK cells isolated on day 8 of the pseudopregnancy / menstruation protocol express genes associated with NK cell effector responses compared to FRT NK cells in mice treated with MPA and compared to splenic NK cells in both models.