7080
While virus derived from the clone containing the M47 mutation retained the ability to immortalize T lymphocytes , the M22 mutant lost the ability to immortalize infected cells .
 ( protein: M47, None) , ( cell type: infected cells, None) , ( cell type: T lymphocytes, None) , ( protein: M22, 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: M47, None) , ( cell type: infected cells, None) , ( cell type: T lymphocytes, None) , ( protein: M22, None) 