13417
Initial signaling through the CD4 receptor played a major role in the sensitization of HIV-infected T cells to undergo apoptosis .
 ( cell type: HIV-infected T cells, None) , ( protein: CD4 receptor, None) , ( protein: CD4, 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: HIV-infected T cells, None) , ( protein: CD4 receptor, None) , ( protein: CD4, None) 