Butyrophilins
Butyrophilins (BTN) are related to the myelin oligodendrocyte protein (MOG) and belong to the immunoglobulin superfamily of transmembrane molecules. They are expressed primarily on secretory and intestinal epithelium. Butyrophilins are a major protein component of milk fat droplets and are necessary for droplet secretion. Additionally, butyrophilins can regulate T cell activation.