CD74 Antibody

This antibody recognizes proteins of 33, 35 and 41kDa, which are identified as various isoforms of CD74. The CD74 antibody epitope is localized in the extracellular domain of CD74. CD74 is a type II transmembrane protein which binds to the peptide binding groove of newly synthesized MHC class II alpha/beta heterodimers and prevents their premature association with endogenous polypeptides. The CD74 molecule plays a critical role in the presentation of peptides, by the MHC class II antigens, to CD4 positive lymphocytes. CD74 is expressed on MHC class II positive cells including B cells, a subset of activated T cells, monocytes, dendritic cells and by various types of carcinomas. CD74 is expressed primarily by antigen presenting cells, such as B-lymphocytes (from before the pre-B cell stage to before the plasma cell stage), macrophages, and monocytes, and many epithelial cells. CD74 antibody stains predominantly germinal center lymphocytes and B-cell lymphomas, but rarely T-cell lymphomas. CD74 antibody has been shown to be useful in differentiating atypical fibroxanthoma (-) from malignant fibrous histiocytoma (+) .