Updated publication reference for PubMed record(s): 29774024. T2 cells stably expressing HLA-DR3 and variable amounts of HLA-DM (none, low, and high, per GFP co-expression) were lysed and HLA-DR3-peptide complexes were isolated via immunoprecipitation. Antigenic peptides were then eluted and quantified by LC-MS/MS to assess presented antigenic epitopes.