Advancements in high-resolution HPLC and mass spectrometry have reinvigorated the application of this technology to identify peptides eluted from immunopurified MHC class I molecules. Three melanoma cell lines were assessed using w6/32 isolation, peptide elution and HPLC purification; peptides were identified by mass spectrometry. A total of 13 829 peptides were identified; 83–87% of these were 8–11 mers. Only approximately 15% have been described before. Subcellular locations of the source proteins showed even sampling; mRNA expression and total protein length were predictive of the number of peptides detected from a single protein. HLA-type binding prediction for 10 078 9/10 mer peptides assigned 88–95% to a patient-specific HLA subtype, revealing a disparity in strength of predicted binding. HLA-B*27-specific isolation successfully identified some peptides not found using w6/32. Sixty peptides were selected for immune screening, based on source protein and predicted HLA binding; no new peptides recognized by antimelanoma T cells were discovered. Additionally, mass spectrometry was unable to identify several epitopes targeted ex vivo by one patient's T cells.
- mass spectrometry
- MHC class I
Pritchard, A. L., Hastie, M. L., Neller, M., Gorman, J. J., Schmidt, C. W., & Hayward, N. K. (2015). Exploration of peptides bound to MHC class I molecules in melanoma. Pigment Cell and Melanoma Research, 28(3), 281-294. https://doi.org/10.1111/pcmr.12357