LC/MS/MS spectra. Comparison of LC/MS/MS spectra for the HLA-A*0201–associated, naturally processed and presented CYP190 peptide isolated from the EBV-transformed B-cell line JY (middle panel) and the myeloma cell line U266 (lower panel) compared with the synthetic homologue (upper panel). The primary sequence of CYP190 is depicted in the upper left corner. Retention times were identical (data not shown), and the fragmentation patterns confirm the CYP190 sequence identity. Similar spectra were obtained from gastric carcinoma, several colorectal adenocarcinomas, and EBV-transformed B-cell lines derived from multiple subjects (data not shown).