CD147

Abstract

This chapter discusses the tissue distribution, structure, and functions of leucocyte antigen CD147. The CD147 antigen has a broad expression pattern in both hamatopoietic and nonhematopoietic tissues in all four species and is upregulated upon cell activation. CD147 is expressed weakly on resting leucocytes, but is strongly upregulated on activated lymphocytes and monocytes. CD147 is expressed on various epithelial cells with some differences between species; for example, rat, mouse, and chicken. The CD147 antigen consists of two IgSF domains, a transmembrane sequence containing a charged residue (Glu) and a cytoplasmic domain of 40 residues. The N-terminal IgSF domain belongs to the C2-set, and the membrane proximal domain belongs to the V-set. This is unusual since most members of the IgSF that contain V- and C2-set domains have the opposite arrangement. Human CD147 (EMMPRIN—extracellular matrix metalloproteinase inducer) on tumor cells is thought to bind an unknown ligand on fibroblasts, which stimulates their production of collagenase and other extracellular matrix metalloproteinases, thus enhancing tumor cell invasion and metastasis. CD147 knockout mice are abnormal in their response to odor, and their lymphocytes show an increased mitogenic response upon mixed lymphocyte reaction.