biostudies-literatureBishop CVOregon National Primate Research CenterNICHD NIH HHSNIH HHS1210-1220https://www.ebi.ac.uk/biostudies/studies/S-EPMC6279079biostudies-literatureUnknown96(6)Our previous flow cytometry results demonstrated a significant increase in neutrophils, macrophages/monocytes, and natural killer (NK) cells in dispersed rhesus monkey corpora lutea (CL) after progesterone (P4) levels had fallen below 0.3 ng/ml for ≥3 days during the natural menstrual cycle. In this study, immunohistochemistry revealed the CD11b+ cells (neutrophils, macrophages/monocytes) present in the CL after luteal P4 synthesis ceased were distributed throughout the tissue. CD16+ cells (presumptive NK cells) were observed mainly near the vasculature in functional CL, until their numbers increased and they became widely distributed in regressing CL. To determine if the immune cells that enter luteal tissue during structural regression are functionally different from those that are preseBiology of reproductionChanges in immune cell distribution and their cytokine/chemokine production during regression of the rhesus macaque corpus luteum.PMC6279079R01 HD020869P51 OD011092Hyzer JBishop CVFicco EBlue SStouffer RLHennebold JDSteinbach RXu FfalseChanges in immune cell distribution and their cytokine/chemokine production during regression of the rhesus macaque corpus luteum.Our previous flow cytometry results demonstrated a significant increase in neutrophils, macrophages/monocytes, and natural killer (NK) cells in dispersed rhesus monkey corpora lutea (CL) after progesterone (P4) levels had fallen below 0.3 ng/ml for ≥3 days during the natural menstrual cycle. In this study, immunohistochemistry revealed the CD11b+ cells (neutrophils, macrophages/monocytes) present in the CL after luteal P4 synthesis ceased were distributed throughout the tissue. CD16+ cells (presumptive NK cells) were observed mainly near the vasculature in functional CL, until their numbers increased and they became widely distributed in regressing CL. To determine if the immune cells that enter luteal tissue during structural regression are functionally different from those that are prese2017-01-01T00:00:00Z2017 Jun2026-07-12T03:12:03.055Z2019-03-27T00:11:10ZS-EPMC62790792857519610.1093/biolre/iox052