HLA class II histocompatibility antigen gamma chain also known as
HLA-DR antigens-associated invariant chain or
CD74 (
Cluster of
Differentiation 74), is a
protein that in humans is encoded by the
CD74 gene. The
invariant chain (Abbreviated
Ii) is a
polypeptide involved in the formation and transport of
MHC class II protein. The cell surface form of the invariant chain is known as CD74.