Young and Moody CD1 glycolipid presentation T cell recognition of glycolipids presented by CD1 proteins Running: CD1 glycolipid presentation

D ow nloaded from Young and Moody CD1 glycolipid presentation The most well known molecular paradigm of antigen recognition by T cells involves partial digestion of proteins to generate small peptides, which bind to major histocompatibility complex (MHC) proteins. Recent studies of CD1, an MHC class I homolog encoded outside the MHC, have revealed that it presents diverse glycolipids to T cells. The molecular mechanism for lipid antigen recognition involves insertion of the lipid portion of antigens into a hydrophobic groove to form CD1-lipid complexes, which contact T cell receptors. Here we examine the known antigen structures presented by CD1, the majority of which have sugar moieties that are capable of interacting with T cell receptors. Recognition of carbohydrate epitopes is precise, and lipid-reactive T cells alter systemic immune responses in models of infectious and autoimmune disease. These findings provide a previously unrecognized mechanism by which cellular immunity can include recognition and response to alterations in many types of carbohydrate structures