870
Nuclear extracts assayed for the presence of ISRE binding factors by electrophoretic mobility shift assays show that ISGF3 is induced by IFN-alpha within 6 h from undetectable basal levels in untreated U937 cells .
 protein: ISGF3; protein: ISRE binding factors; DNA: ISRE; protein: IFN-alpha; cell line: U937 cells
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 protein: ISGF3; protein: ISRE binding factors; DNA: ISRE; protein: IFN-alpha; cell line: U937 cells