9900
HeLa cells stably or transiently transfected with mutant CIITA constructs showed up to 99% suppression of MHC class II antigen induction by IFN-gamma and marked suppression of HLA-DRA mRNA expression .
 ( DNA: mutant CIITA constructs, None) , ( protein: IFN-gamma, None) , ( cell line: HeLa cells, None) , ( RNA: HLA-DRA mRNA, None) , ( protein: MHC class II, None) , ( protein: CIITA, 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:
 ( DNA: mutant CIITA constructs, None) , ( protein: IFN-gamma, None) , ( cell line: HeLa cells, None) , ( RNA: HLA-DRA mRNA, None) , ( protein: MHC class II, None) , ( protein: CIITA, None) 