CD1d is a type I transmembrane protein and member of the MHC family, with a molecular weight ranging from 43-49 kD, depending on the glycosylation degree. CD1d is expressed by antigen presenting cells such as dendritic cells, monocytes, macrophages and B cells; also expressed by thymocytes and intestinal epithelial cells. CD1d present glycolipids to iNKT cells that recognize them by their Vα14i TCR.