4757
The present study examines the mechanisms involved in LPS -mediated induction of HIV expression in U1 cells , a promonocytic cell line chronically infected with HIV .
 ( cell line: U1 cells, None) , ( cell line: promonocytic cell line, 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 line: U1 cells, None) , ( cell line: promonocytic cell line, None) 