1621
To investigate the mechanisms accounting for the impaired responses to gamma interferon , a model system for examining overall changes in protein tyrosine phosphorylation , activation of Jak1 and Jak2 and phosphorylation of Stat1 was developed in phorbol 12-myristate 13-acetate -differentiated U-937 cells .
 protein: gamma interferon; protein: Jak1; protein: Stat1; cell line: phorbol 12-myristate 13-acetate -differentiated U-937 cells; protein: Jak2
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: gamma interferon; protein: Jak1; protein: Stat1; cell line: phorbol 12-myristate 13-acetate -differentiated U-937 cells; protein: Jak2