The TCR of NKT cells recognize endogenous self glycolipid antigen presented by CD1d molecules on antigen presenting cells (APCs). Antigen-presenting dendritic cells engulf certain glycolipids from human cells and degrade them with their lysomes. These glycolipid epitopes are then bound to CD1d molecules produced by the APC and transported to the surface of the cell where they can be presented to theTCR of NKT cells to induce NKT cell activation.