14750
OBJECTIVE: To examine the inter-relationship between HIV-1 infection and the cell surface receptors for tumor necrosis factor (TNF)-alpha , an immunoregulatory cytokine that can enhance HIV-1 replication .
 ( protein: tumor necrosis factor (TNF)-alpha, 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: tumor necrosis factor (TNF)-alpha, None) 