Figure 2.

Representative targeted MS data

Targeted MS was used to detect the 10mer KRAS^G12V HLA-A3 superfamily neoantigen VVVGAVGVGK in (A) A375 cells engineered to express both the KRAS^G12V mutation and HLA-A∗11:01, (B) SW620 cells that naturally express the KRAS^G12V mutation but were engineered to express HLA-A∗11:01, and (C) NCI-H441 cells that naturally express both the KRAS^G12V mutation and HLA-A∗03:01. The top panels specify the KRAS mutation and HLA-I molecule present in each sample. The middle panels contain the mass spectra for the peptide detected in each sample (top), and the mass spectra for the heavy isotope-labeled synthetic peptide (bottom) used to confirm the detections. The bottom panels show mass error in parts per million (ppm) of the a-ions (purple), b-ions (blue), and y-ions (red) for the endogenous (top) and heavy isotope-labeled synthetic (bottom) mass spectra. Data from the same heavy isotope-labeled synthetic peptide was used in this figure. See also Data S2.