5661
In contrast, APC pulsed with Ala -substituted peptides 430-444 , 442A or 433-442A at neutral pH failed to stimulate the T cell clone , while APC pulsed at acidic pH and subsequently washed led to successful T cell activation .
 ( cell type: APC, None) , ( cell type: APC, None) , ( cell line: T cell clone, 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: APC, None) , ( cell type: APC, None) , ( cell line: T cell clone, None) 