Reading within the lines: naturally processed peptides displayed by MHC class I molecules

A typical mammalian cell contains tens of thousands of different gene products. Snippets of this genetic information are displayed on the cell surface by MHC class I molecules as short peptides for immune surveillance by CD8+ T lymphocytes. Genetic and biochemical analysis of these peptides is revealing novel sources and mechanisms by which these peptide/MHC class I complexes arise.