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This study demonstrates that human immunodeficiency virus type 1 ( HIV-1 ) Tat protein amplifies the activity of tumor necrosis factor ( TNF ), a cytokine that stimulates HIV-1 replication through activation of NF-kappa B .
 ( protein: human immunodeficiency virus type 1 ( HIV-1 ) Tat protein, None) , ( protein: NF-kappa B, None) , ( protein: tumor necrosis factor, None) , ( protein: TNF, 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: human immunodeficiency virus type 1 ( HIV-1 ) Tat protein, None) , ( protein: NF-kappa B, None) , ( protein: tumor necrosis factor, None) , ( protein: TNF, None) 