7194
Sustained proliferation of erythroid progenitors could be induced equally well from purified erythroid burst-forming units ( BFU-E ), from CD34(+) blast cells , and from bone marrow depleted from CD34(+) cells .
 ( cell line: BFU-E, None) , ( cell type: CD34(+) blast cells, None) , ( cell line: purified erythroid burst-forming units, None) , ( cell type: erythroid progenitors, None) , ( cell type: CD34(+) cells, 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 line: BFU-E, None) , ( cell type: CD34(+) blast cells, None) , ( cell line: purified erythroid burst-forming units, None) , ( cell type: erythroid progenitors, None) , ( cell type: CD34(+) cells, None) 