Identification of Human Trophoblast in vitro

Abstract

WHILE investigating the antigenicity of human trophoblast and its possible role in the toxaemias of pregnancy, we wished to set up pure tissure cultures of trophoblast. Placental tissue in explant and monolayer culture gives rise to a mixed population of cells, the identification of which is difficult because they undergo morphological and physiological changes in vitro. Existing methods for identifying trophoblast in vitro include cytology^1,2, enzyme histochemistry¹ and the demonstration of chorionic gonadotrophin production^3,4. Thiede¹ distinguished three cell types in cultures of chorionic villi: fibroblasts, epithelioid cells and giant multinucleated cells. He suggested that these originated from mesenchyme, cytotrophoblast and syncytio-trophoblast respectively, but emphasized the unreliability of morphological criteria. The histochemical localization of alkaline phosphatase in epithelioid and multinucleate cell types¹ is considered compatible with an origin from trophoblast in view of the distribution of this enzyme in the placenta found by several workers^5–9. Soma, Ehrmann and Hertig³ found that the goriadotrophic activity of the culture medium declined in concert with the disappearance of giant multinucleated cells, suggesting that these might be trophoblastic in origin.