18
Adenovirus (Ad) infection and E1A transfection were used to model changes in susceptibility to NK cell killing caused by transient vs stable E1A expression in human cells .
 ( protein: E1A, None) , ( cell type: human cells, None) , ( protein: E1A, 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:
 ( protein: E1A, None) , ( cell type: human cells, None) , ( protein: E1A, None) 