12674
These results suggest that activation of Stat4 , which is necessary for the differentiation of naive T cells into polarized Th1 cells , is not sufficient to induce phenotype reversal of human Th2 cells .
 ( cell type: naive T cells, None) , ( cell type: Th1 cells, None) , ( protein: Stat4, None) , ( cell type: human Th2 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 type: naive T cells, None) , ( cell type: Th1 cells, None) , ( protein: Stat4, None) , ( cell type: human Th2 cells, None) 