In vitro cytostatic properties of unactivated rat Kupffer cells.

Kupffer cells from the liver of normal rats were checked for their natural cytostatic capabilities using an in vitro target cell growth inhibition assay. A strong cytostatic effect was observed on an human tumor cell line and was shown to be exerted on various transformed or normal target cells with only small differences in their susceptibility. The inhibition of target cell proliferation was shown to depend on the effector/target cell ratio. Different experimental data suggest that an intimate membranal contact between Kupffer cells and target cells is required.