In vitro growth stimulation of human ovarian cancer cells by xenogeneic peritoneal macrophages.

For improvement of the in vitro growth rate of human ovarian tumors, an irradiated xenogeneic feeder layer of adherent peritoneal cells was added to such cultures. This adherent peritoneal cell population was obtained from oil-primed adult (C57BL/6J x DBA/2J)F1 mice and contained predominantly macrophages. After irradiation of the feeder layer with 3,000 rad 137Cs, cell suspensions prepared from fresh, solid human ovarian cancers were cocultivated with the feeder cells. Two end points were used to evaluate the growth enhancement added by such a feeder layer: 1) Primary monolayer cultures of ovarian tumors were successfully grown in continuous culture through five or more serial subcultures in 25 of 64 different patient specimens studied. Control cultures without the feeder layers did not continue growing through serial subcultures. 2) With the use of the soft agar clonogenic assay, addition of the feeder layer to the petri dishes increased the number of tumor cell colonies in each of six separate experiments, compared to the number seen in control plates without the feeder layer.