947
The Epstein-Barr virus ( EBV ) nuclear antigen 2 ( EBNA-2 ) protein is essential for the immortalization of human primary B cells by EBV .
 ( protein: Epstein-Barr virus ( EBV ) nuclear antigen 2, None) , ( cell type: human primary B cells, None) , ( protein: EBNA-2, 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: Epstein-Barr virus ( EBV ) nuclear antigen 2, None) , ( cell type: human primary B cells, None) , ( protein: EBNA-2, None) 