6894
Our results indicate that the signaling events initiated in PBMCs by oligomerization of CD4 at the D1/ CDR2-loop can trigger HIV-1 upregulation in infected individuals .
 ( protein: CD4, None) , ( cell type: PBMCs, None) , ( protein: D1/ CDR2-loop, None) , ( protein: CDR2-loop, 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: CD4, None) , ( cell type: PBMCs, None) , ( protein: D1/ CDR2-loop, None) , ( protein: CDR2-loop, None) 