4181
In contrast, a high level of bcl-2 protects cells in vitro and in vivo from the viral protease and prevents cell death following HIV infection of human lymphocytes , while reducing the yields of viral structural proteins , infectivity, and tumor necrosis factor alpha .
 ( protein: tumor necrosis factor alpha, None) , ( cell type: human lymphocytes, None) , ( protein: viral protease, None) , ( protein: viral structural proteins, None) , ( protein: bcl-2, 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 alpha, None) , ( cell type: human lymphocytes, None) , ( protein: viral protease, None) , ( protein: viral structural proteins, None) , ( protein: bcl-2, None) 