CD1d-Restricted Natural Killer T Cells

Natural killer T (NKT) cells that express the semi-invariant T-cell receptor are innate-like lymphocytes whose functions are controlled by self and foreign glycolipid ligands. Such ligands are presented by the antigen-presenting, MHC class I-like molecule CD1d, which belongs to a family of lipid antigen-presenting molecules collectively called CD1. Activation of NKT cells in vivo results in rapid release of copious amounts of effector cytokines and chemokines with which they regulate innate and adaptive immune responses to pathogens, certain types of cancers and self-antigens. The nature of CD1d-restricted ligands, the manners in which they are recognised and the unique effector functions of NKT cells suggest an immunoregulatory role for this T-cell subset. Their ability to respond fast and our ability to steer NKT cell cytokine responses to altered lipid ligands make them an important target for vaccine design and immunotherapies against autoimmune diseases. This article summarises our current understanding of CD1d-restricted NKT cell biology and how these innate-like lymphocytes control inflammation.