CD1d is a non-polymorphic, MHC class I-like molecule that forms a heterodimer with 尾2-microglobulin and plays a crucial role in the immune system by presenting lipid antigens to invariant Natural Killer T (iNKT) cells. These lipid antigens can be derived from both self and non-self sources, including bacterial glycolipids and tumor-derived lipids. CD1d is expressed on various cell types, including myeloid and lymphoid cells, as well as epithelial and vascular smooth muscle cells. It is involved in regulating both innate and adaptive immune responses and has been implicated in antimicrobial, antitumor, and autoimmune activities. Additionally, CD1d is associated with diseases such as pulmonary tuberculosis and certain cancers.