EpCAM/CD3 Antibodies

Target Information

Ep-CAM (epithelial adhesion molecule, epithelial specific antigen, ESA) is a transmembrane glycoprotein expressed in the epithelium with a molecular weight of approximately 40 kDa, which functions as an epithelial cell adhesion molecule. Ep-CAM functions as a homotypic calcium-independent cell adhesion molecule, and has a direct impact on cell cycle, proliferation and metabolism of epithelial cells and fibroblasts due to its ability to rapidly induce the proto-oncogene c-myc and the cell cycle regulating genes cyclin A and E. Ep-CAM mediates Ca2+-independent homotypic interactions. Formation of Ep-CAM-mediated adhesions have a negative regulatory effect on adhesions mediated by classic cadherins, which may have strong effects on the differentiation and growth of epithelial cells. Ep-CAM overexpression was suggested to be associated with enhanced epithelial proliferation. Ep-CAM is highly expressed in human carcinomas, and is a marker for tumors of epithelial lineage. Ep-CAM is expressed on baso-lateral cell surface in most simple epithelia and many carcinoma types. Also, Ep-CAM reportedly distinguishes adenocarcinomas from pleural mesotheliomas.

The CD3 complex, composed of gamma, delta, epsilon, and zeta subunits, is essential for the assembly, trafficking, and surface expression of the T cell receptor (TCR) complex. These subunits are structurally related members of the immunoglobulin superfamily and are encoded by closely linked genes on human chromosome 11. CD3 is expressed by thymocytes in a developmentally regulated manner and by all mature T cells, but not on B or NK cells. The CD3 subunits play a crucial role in transducing antigen-recognition signals into the cytoplasm of T cells. The cytoplasmic tails of CD3 subunits contain a double tyrosine-based motif that associates with cytoplasmic signal transduction molecules, mediating T cell activation through the TCR. Crosslinking of the TCR initiates intracellular biochemical pathways that result in cellular activation, proliferation, and potentially growth arrest and cell survival. CD3 is present on 68-82% of normal peripheral blood lymphocytes, 65-85% of thymocytes, and Purkinje cells in the cerebellum. Decreased percentages of T lymphocytes may be observed in some autoimmune diseases. Defects in the CD3 gene are associated with CD3 immunodeficiency, highlighting its importance in immune function and regulation.