5914
The strong association of the disease with an epitope within the HLA-DR chain shared between various alleles of HLA-DR4 and DR1 emphasizes the importance of antigen presentation .
 DR1, HLA-DR4, HLA-DR chain, epitope
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 DR1, HLA-DR4, HLA-DR chain, epitope