Retention of class I/SIINFEKL complexes by DC subsets.

MACS-purified CD11c⁺ DCs were pulsed with SIINFEKL peptide at the indicated concentrations, thrice washed, then chased for the indicated periods of time in absence of peptide. The levels of retained SIINFEKL-class I–peptide complexes on the DC subsets were determined using the 25-D1.16 mAb with antimouse-PE and by double labeling with CD8α-FITC. The mean fluorescent intensities of 25-D1.16 staining of the indicated DC subsets are plotted. The background staining of 25-D1.16 on unpulsed DCs was similar to that of an irrelevant mouse IgG1 isotype control (not shown).