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Several mutants derived from transformed human B cell lines are defective in expressing major histocompatibility complex (MHC) class II genes .
 cell line: transformed human B cell lines; DNA: major histocompatibility complex (MHC) class II genes
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 cell line: transformed human B cell lines; DNA: major histocompatibility complex (MHC) class II genes