7186
These results indicate that CTLA-4 signaling inhibits events early in T cell activation both at IL-2 transcription and at the level of IL-2 -independent events of the cell cycle , and does not simply oppose CD28 -mediated costimulation .
 ( protein: CTLA-4, None) , ( protein: IL-2, None) , ( protein: IL-2, None) , ( protein: CD28, 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: CTLA-4, None) , ( protein: IL-2, None) , ( protein: IL-2, None) , ( protein: CD28, None) 