Isolation of cell island cytotrophoblast from first trimester human placenta, and comparison of antigen expression on villus and extravillus cytotrophoblast

Abstract

Antigen expression of the various trophoblast populations in human first trimester placenta was tested using a panel of anti-trophoblast monoclonal antibodies on frozen tissue sections. A method was developed for the isolation of extravillus cytotrophoblast from cell islands, up to 99% pure. These cells were used as an immunogen in mice and the resulting monoclonal antibody, designated NDOG5, was characterized. In first trimester tissue, NDOG5 binds to the cell islands and to the interstitial and endovascular cytotrophoblast of the maternal decidua. At term, the antibody also labels a subset of cytotrophoblast in the amniochorion. It does not react with either syncytiotrophoblast or villus cytotrophoblast. The antigen detected by NDOG5 is specific for extravillus cytotrophoblast, and is not present on amniotic epithelium, decidual cells, or villus stromal cells. NDOG5 does not bind to any normal adult human tissues tested and is not present on breast or cervical carcinoma cells. In relation to other anti-trophoblast antibodies, NDOG5 defines a unique subset of extravillus cytotrophoblast.