The cytostatic activity of cultured Kupffer cells.

The cytostatic activity of a population of cultured syngeneic and allogeneic Kupffer cells against the K31 tumour cell line has been studied in vitro. The addition of purified populations if Kupffer cells to the tumour cell line resulted in a reduction in the uptake of 125IUdR by the tumour cells. This cytostatic activity was not due to a non-labile supernatant effect. There was a progressive loss of the cytostatic activity of the Kupffer cells as their time in culture increased. The experiments show that Kupffer cells, like other macrophages, possess cytostatic activity in vitro which is not genetically restricted.