14819
One signal can be delivered by the antigen-specific T-cell receptor , and the second signal is provided by the costimulatory molecule(s) delivered by the antigen-presenting cell .
 ( cell type: antigen-presenting cell, None) , ( protein: antigen-specific T-cell receptor, 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: antigen-presenting cell, None) , ( protein: antigen-specific T-cell receptor, None) 