Establishment and characterization of a cytotrophoblast cell line from normal placenta of human origin.

A cell line has been established from human placentae at the first trimester of normal pregnancy. The cell line was obtained by culture of purified cytotrophoblast cells in serum-free medium supplemented with epidermal growth factor, insulin, dexamethasone and 0.1% bovine serum albumin. The cells can be subcultured for >30 passages in one to three splits. All the cells were mononuclear epithelial-like cells positive to cytokeratin 18, gonadotrophin-releasing hormone (GnRH), neuropeptide Y, neurotensin, leucine-enkephalin, dopamine and 5-hydroxytryptamine immunocytochemical staining. The cells secreted GnRH, progesterone and oestradiol (in the presence of testosterone) but little human chorionic gonadotrophin and no beta-endorphin. The cell line showed human karyotypes and had a population doubling time of 48 h in serum-free medium. However, the cells would stop growing in the medium containing fetal bovine serum. A normal cytotrophoblast cell line established in serum-free medium will be particularly useful in the study of cytotrophoblast cell proliferation and differentiation.