title: Effect of human monocyte-released cytostatic factors on target cell DNA synthesis, protein synthesis, and ATP content.
abstract: Cultured human monocytes activated in vitro with lymphokines and lipopolysaccharide release cytostatic protein factors that may be separated by ion-exchange chromatography into two populations, termed cytostatic factors I and II (CF I and II). The effect of CF I and II on target cell DNA synthesis, protein synthesis, and ATP content and the possible presence of a CF-associated protease activity were investigated. Inhibition of DNA synthesis was detected 4 h after addition of either CF I or CF II, whereas inhibition of protein synthesis was first detected after 10-15 h. Moreover, 20 h after addition of either CF I or CF II the average DNA synthesis per cell was inhibited by 25-35%, as compared with 10-15% inhibition of protein synthesis. No significant alteration in cellular ATP content was observed in cells culture up to 25 h with either CF I or CF II. Thus, neither protein synthesis nor generation of ATP appeared to be primary targets of either CF I or CF II, but the factors may act more directly on DNA synthesis. Protease activity was not associated with either CF I or CF II, and the factors thus differed from a previously reported cytolytic protease released from activated murine macrophages.
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D004247:DNA / Q000096:biosynthesis; D006131:Growth Inhibitors / Q000302:isolation & purification / Q000502:physiology*; D006801:Humans; D007108:Immune Tolerance; D008970:Molecular Weight; D009000:Monocytes / Q000201:enzymology / Q000276:immunology*; D010447:Peptide Hydrolases / Q000378:metabolism; D014176:Protein Biosynthesis
chemical_list: D006131:Growth Inhibitors; D000255:Adenosine Triphosphate; D004247:DNA; D010447:Peptide Hydrolases