Mining the plasma immunopeptidome for cancer peptides as biomarkers and beyond

摘要

The class I MHC-CD8~+-T-cell immunosurveillance system con stitutes a major component of the adaptive immune system in mammals and other jawed vertebrates. All cell types (except erythrocytes) constitu tively express MHC class I molecules, which are comprised of a type I membrane anchored glycoprotein (heavy chain) non covalently bound to β_2-microglobulin (β_2m) and a peptide typically of 8-11 resi dues. Peptides derive from proteins syn thesized by cells, often from defective ribosomal products (DRiPs), which are a subset of nascent proteins that are rapidly shunted to proteasomes for degradation because of either stochastic errors in gene expression (transcription, translation, pro tein folding or assembly) or a deliberate process of translating standard and non standard mRNAs for the purpose of immu nosurveillance (1).