Reverse-phase HPLC separation of peptide pools eluted from HLA-A, B/C, and DR molecules. The chromatograms represent the peptide repertoire as detected by UV absorbance at 210 nm (20 mAU full scale, Y axis). X axis, time (0 to 120 minutes). The gradient was run for 0 to 5 minutes at 2% acetonitrile/TFA solution B and then for 5 to 120 minutes at 2% to 80% acetonitrile/TFA solution B, with a flow rate of 0.150 mL/min. (Top panel) HLA-A2 eluted peptides. (Middle panel) HLA-B63 and HLA-B5101 eluted peptides. (Bottom panel) HLA-DR1 and HLA-DR3 eluted peptides.