CD305, also known as LAIR-1 (leukocyte-associated Ig-like receptor-1), is a 40 kD type I transmembrane glycoprotein. LAIR-1 and LAIR-2 are the only members of the LAIR family in the Ig superfamily. LAIR-1 is an inhibitory molecule characterized by ITIMs in the cytoplasmic domain and collagen ligands. CD305 is expressed on NK cells, T cells, B cells, monocytes, dendritic cells, eosinophils, basophils and mast cells. LAIR-1 functions in the inhibition of cell cytotoxicity, cell activation, proliferation and differentiation.