CD3e, epsilon (CD3E) is a polypeptide subunit of the T-cell receptor-CD3 complex, which plays an important role in T-cell development and the adaptive immune response. Along with its associated CD3 subunits, it couples activation of T-cell receptors by antigen-presenting cells to intracellular signal transduction pathways. Mutations in the CD3E gene cause immunodeficiency, and the gene may be linked to susceptibility to type 1 diabetes in women. CD3E is expressed in T cells and is found in the bone marrow and tissues of the immune system such as lymph node, spleen, appendix, and tonsil. CD3E antibodies are used to identify T cells in benign and malignant disorders. References: Proc Natl Acad Sci USA. 1998;95(25):14909-14914. doi: 10.1073/pnas.95.25.14909. Nat Genet. 1993;3(1):77-81. doi: 10.1038/ng0193-77. J Clin Invest. 2004;114(10):1512-1517. doi: 10.1172/JCI22588. Clin Exp Immuno. 1991;83(1):69-73. doi: 10.1111/j.1365-2249.1991.tb05590.x.