BIOLOGICAL EFFECTS OF A NOVEL INTESTINAL PEPTIDE - INHIBITING ENTEROCYTOGENIN ON CULTURED 3T3 MOUSE FIBROBLASTS AND L5178Y MOUSE LYMPHOMA-CELLS

The effects of a new intestinal peptide, inhibiting enterocytogenin (I EG) derived from pig intestinal mucosa were studied in vitro on 3T3 mo use fibroblasts and L5178Y mouse lymphoma cell line. IEG caused consid erable growth inhibition together with specific morphological changes, necrotic effects as well as formation of monolayers at the highest co ncentration applied (1000 mu g/ml). A biologically active fraction (IE G-BAF) derived by further purification of IEG by gel-filtration, prove d to possess most of the described activity. The concentrations of IEG and IEG-BAF inhibiting the growth of L5178Y lymphoma cells by 50%, (I C50 values) were calculated to be 759 mu g/ml and 19? mu g/ml, respect ively. IEG-BAF has a molecular mass of 4450 +/- 180 Da and is most pro bably a peptidylnucleotidate as revealed by spectral analysis.