CD74 antigen, DHLAG, HLA class II histocompatibility antigen gamma chain, HLADG, HLA-DR antigens-associated invariant chain, Ia antigen-associated invariant chain, Ia-GAMMA, Ii, p33, protein 41

CD74 represents a type II integral membrane protein known as MHC Class II-associated invariant chain (Mr 43, 41, 35, 33kD). It is moderately expressed on B cells, and weakly on monocytes and macrophages. CD74 is also found on a subset of activated T cells, Langerhans cells, dendritic cells and some epithelial cells. CD74 may play a role in antigen processing and presentation through intracellular transport and expression of Class II molecules on the cell surface.1-4