ANTIGEN PRESENTATION BY CD1 AND MHC-ENCODED CLASS I-LIKE MOLECULES

Three known lineages of antigen-presenting molecules restrict T-cell r esponses to microbial antigens: MHC class I and MHC encoded class I li ke molecules present peptides derived from the proteolysis of intracel lular pathogens, MHC class II molecules present peptides derived from the proteolysis of extracellular pathogens and CD1 molecules present u nique microbial lipids and glycolipids. Recent studies have indicated that CD1 molecules mediate a novel system of antigen presentation and that MHC-encoded class I-like molecules can present unique subsets of intracellularly derived peptides.