Conserved lipid and peptide presentation functions of nonclassical class Imolecules

CD1-mediated lipid presentation to natural killer (NK) T cells is highly co nserved between rodents and humans. Similarly, HLA-E- or Qa-1-mediated pres entation of class-I-derived leader peptides to inhibitory NK receptors is f unctionally conserved. Here, Mitchell Kronenberg: and colleagues discuss th ese two systems, which provide the first evidence for a conserved ligand-bi nding or presentation function for nonclassical class I molecules.