14840
Two stable B cell lines were established: R59Z activator cells were used to induce lytic EBV expression in a constitutive manner by the production of the BZLF 1 trans-activator ( Zta ).
 ( protein: BZLF 1 trans-activator, None) , ( cell line: R59Z activator cells, None) , ( protein: Zta, None) , ( cell line: B cell lines, 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: BZLF 1 trans-activator, None) , ( cell line: R59Z activator cells, None) , ( protein: Zta, None) , ( cell line: B cell lines, None) 