Reacts with five invariable CD3 chains (designated as and ) with molecular weight ranging from 16-28 kDa. CD3 is expressed, typically at high levels, on peripheral T cells and majority of T cell neoplasms. Thymocytes express CD3 at different level on the cell surface in the course of differentiation and, in cortical thymus, CD3 is predominantly Intracytoplasmic. The CD3 complex is closely associated at the lymphocyte cell surface with T cell antigen receptor (TCR) and is involved in transducing antigen-recognition signals into cytoplasm of T cells and in regulating the cell surface expression of the TCR complex. Primary antibodies are available purified, or with a selection of fluorescent CF® Dyes and other labels. CF® Dyes offer exceptional brightness and photostability. Note: Conjugates of blue fluorescent dyes like CF®405S and CF®405M are not recommended for detecting low abundance targets, because blue dyes have lower fluorescence and can give higher non-specific background than other dye colors.