12976
Using tetanus toxoid specific and HLA-DR-restricted T lymphocytes , we show that polarized intestinal epithelial cells directed to express HLA-DR molecules are able to initiate class II processing only after internalization of antigen from their apical surface.
 ( cell type: polarized intestinal epithelial cells, None) , ( protein: HLA-DR molecules, 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: polarized intestinal epithelial cells, None) , ( protein: HLA-DR molecules, None) 