7959
However, only low levels of IFN-gamma or IFN-gamma -producing cells were detected in airway tissue in all subjects.
 ( cell type: IFN-gamma -producing cells, None) , ( protein: IFN-gamma, None) , ( protein: IFN-gamma, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( cell type: IFN-gamma -producing cells, None) , ( protein: IFN-gamma, None) , ( protein: IFN-gamma, None) 