7182
Here, we have analyzed the mechanisms involved in CTLA-4 -mediated inhibition of T cell activation of naive CD4+ T cells using Ab cross-linking .
 ( cell type: CD4+ T cells, None) , ( protein: CTLA-4, 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:
 ( cell type: CD4+ T cells, None) , ( protein: CTLA-4, None) 