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Interestingly, in CIITA -transfected cell hybrids , cell surface expression of the human HLA-DQ heterodimer was not observed.
 CIITA -transfected cell hybrids, CIITA, human HLA-DQ heterodimer
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:
 CIITA -transfected cell hybrids, CIITA, human HLA-DQ heterodimer