Glycolipid targets of CD1-mediated T-cell responses

Members of the CD1 family of antigen-presenting molecules bind and present a variety of mammalian and microbial glycolipids for specific recognition b y T cells. CD I proteins accomplish their antigen-presenting function by bi nding the alkyl chains of the antigens within a deep. hydrophobic groove on the membrane distal surface of CD1, making the hydrophilic element, of the antigen available for contact with the variable regions of antigen-specifi c T-cell receptors. Most models of CD1-restricted T cells function in infec tious. neoplastic, or a autoimmune diseases and are based on the premise th at CD1-restricted T-cell responses are initiated by alterations in Cellular glycolipid content. Although a growing number of self, altered self and fo reign glycolipid antigens have been identified, the cellular mechanisms tha t Could lead to the generation of antigenic glycolipids within cells, or co ntrol the presentation of particular classes of altered self or microbial g lycolipids in disease states have only recently come under investigation. H ere we review the Structures of known glycolipid antigens for T cells and d iscuss how the chemical nature of these antigens, which is quite different from that of peptides. influences their recognition by T cells.