Figure 5. Purification and identification of peptidases controlling cross-priming of CD8⁺ T cells.

(A and B) Fx fractions from anion exchange chromatography were collected, desalted, and concentrated. Titrated amounts of these fractions were added to the CFSE-labeled OT-I splenocytes in the presence of F_9–23 and 20 μg/ml OVA, and T cell activation was analyzed. Results are representative of 3 independent experiments. (C and D) Representative spectra of DPP-3 and TOP-1. Ions belonging to the y- and b-ion series are indicated. The iTraq-label region is shown magnified. The reporter ion labels 114, 115, 116, and 117 are replaced by the fraction numbers (Fx33, Fx34, Fx35, and Fx36, respectively) from anion exchange chromatography onto Resource-Q (GE). Relative intensities are indicated.