Placental CSF-like activity

We have examined amniotic fluid and cultured supernatants of a variety of placental cells for the presence of colony-stimulating factor (CSF) activity. The supernatants of cultured human choriocarcinoma cell lines, Jeg and Jar, contained CSF activity that induced the formation of granulocyte-macrophage colony-forming unit (CFU-GM) and multipotential colony-forming unit (CFU-GEMM) colonies. Cultured supernatants of nontransformed rat placental cells, chorionic villous cells, and amniotic fluid also induced CFU-GM colonies.