513
This mechanism may be important in the activation of HIV expression from latently infected CD4+ T cells , especially in lymphoid organs where cell to cell contact is conducive to receptor-ligand interactions .
 ( cell type: T cells, None) , ( cell line: CD4+ T cells, 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 cells, None) , ( cell line: CD4+ T cells, None) 