12718
At the same time there was no change in the level of expression of the cell surface antigenes CD33 , CD34 , CD45 , CD71 and glycophorin A .
 ( protein: CD33, None) , ( protein: CD34, None) , ( protein: glycophorin A, None) , ( protein: cell surface antigenes, None) , ( protein: CD45, None) , ( protein: CD71, 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: CD33, None) , ( protein: CD34, None) , ( protein: glycophorin A, None) , ( protein: cell surface antigenes, None) , ( protein: CD45, None) , ( protein: CD71, None) 