Identification by flow cytometry of the prostaglandin-producing cell populations of term human decidua

Human term decidua produces prostaglandins (PGs) which have been implicated in the initiation of human parturition. Using flow cytometry to isolate pure cell populations, we have investigated the cell types responsible for decidual PG production. Cell dispersions were prepared enzymatically from decidua vera isolated from term placentae, and were incubated in Dulbecco's Modified Eagle's Medium containing 0.25% bovine serum albumin at 37 degrees C. PGF2 alpha and PGE2 output were measured by radioimmunoassay of the conditioned medium. Production of PGF2 alpha (fmol/10(6) cells per 3 h) exceeded that of PGE2 at 273 (108-322) versus 97 (38-127) respectively (median (range]. The decidual cell dispersions were then incubated with monoclonal antibodies (anti-CD45 which labels the leukocyte common antigen or anti-human leukocyte antigen class II (HLA-DR) which is specific for macrophages in this tissue) and sorted by flow cytometry. The resultant antibody-positive and -negative cell populations were incubated and PG production was measured. Controls showed that antibody labelling and sorting did not alter PG production. PGF2 alpha and PGE2 output by bone marrow-derived (CD45-positive) cell populations exceeded that of non-bone marrow-derived (CD45-negative) cells. Furthermore, we were able to demonstrate that the HLA-DR-positive macrophage population had the highest PGF2 alpha and PGE2 production rates in human term decidua in vitro.