13527
In this study, various sets of somatic cell hybrids , generated by the fusion of epithelial cell lines with B-lymphoblastoid cell lines , were analyzed for the expression of major histocompatibility complex (MHC) class II antigens .
 ( protein: major histocompatibility complex (MHC) class II antigens, None) , ( cell line: epithelial cell lines, None) , ( cell line: somatic cell hybrids, None) , ( cell line: B-lymphoblastoid cell lines, 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:
 ( protein: major histocompatibility complex (MHC) class II antigens, None) , ( cell line: epithelial cell lines, None) , ( cell line: somatic cell hybrids, None) , ( cell line: B-lymphoblastoid cell lines, None) 