CD1 (cluster of differentiation 1) is a family of glycoproteins expressed on the surface of various human antigen-presenting cells. They are related to the class I MHC molecules, and are involved in the presentation of lipid antigens to T cells. However their precise function is unknown.
CD1 glycoproteins can be classified primarily into two groups which differ in their lipid anchoring.
CD1e is an intermediate form, expressed intracellularly, the role of which is currently unclear.
Group 1 CD1 molecules have been shown to present foreign lipid antigens, and specifically a number of mycobacterial cell wall components, to CD1-specific T cells.
The natural antigens of group 2 CD1 are not well-characterized, but a synthetic glycolipid, alpha-galactosylceramide, originally isolated from a compound found in a marine sponge, has strong biologic activity.
CD1 is the unofficial name of an untitled album by English industrial band Throbbing Gristle, released in 1986 through record label Mute.
The album is their first CD release and has a catalog number of "CD1", hence the adoption of the name. The album has been called "undoubtedly [...] in part responsible for the growing importance of the industrial scene in the late 1980s." The album is an TEAC 8-track recording done on 18 March 1979 at the band's Industrial Records Studio in Hackney, London.
CD1 was released in 1986 through record label Mute.
Spin Alternative Record Guide called it "an album of meandering studio experiments".