390
These may partly account for the differential effects of B7 and LFA-3 costimulation on IL-2 expression .
 ( protein: IL-2, None) , ( protein: B7, None) , ( protein: LFA-3, 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: IL-2, None) , ( protein: B7, None) , ( protein: LFA-3, None) 