5334
Activation of T lymphocytes requires the combined signaling of the T cell receptor and costimulatory molecules such as CD28 .
 ( cell type: T lymphocytes, None) , ( protein: T cell receptor, None) , ( protein: costimulatory molecules, 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:
 ( cell type: T lymphocytes, None) , ( protein: T cell receptor, None) , ( protein: costimulatory molecules, None) , ( protein: CD28, None) 