Release of anti-PAF activity from PAF-binding human ovarian cancer cells in culture.

The human ovarian cancer cell line EFO-27 in culture spontaneously produced anti-PAF activity, which eluted from HPLC in the range of synthetic PAF. The activity therefore appears to be due to an antagonistic PAF-analogue. It was detected by a suppressed PAF-induced platelet aggregation in vitro. EFO-27 cells were found to be able to bind synthetic PAF with saturable binding kinetics. This binding led to reduced cell proliferation. The production of anti-PAF activity by EFO-27 cells resembles an autocrine growth regulation in the light of recent findings that other malignant transformed cell lines produce PAF-like activity in vitro if stimulated appropriately.