Culture supernatants from uninduced U937 cells were also found to activate an ISRE cloned upstream of the luciferase reporter gene , indicating the presence of endogenous IFN activity equivalent to approximately 0 . 3 to 0 . 5 IU/mL .
culture supernatants from uninduced u937 cells were also found to activate an isre cloned upstream of the luciferase reporter gene , indicating the presence of endogenous ifn activity equivalent to approximately 0 . 3 to 0 . 5 iu/ml .
O O O B-cell_line I-cell_line I-cell_line O O O O O O B-DNA_domain_or_region O O O O B-protein_molecule O O O O O O O B-protein_family_or_group I-protein_family_or_group O O O O O O O O O O O O O