Reacts with five invariable CD3 chains designated CD3y, CD3d, CD3e, CD3f, and CD3n with molecular weight ranging from 16-28 kDa. CD3, also known as T3, is a member of the immunoglobulin superfamily that plays a role in antigen recognition, signal transduction, and T cell activation. It is found on all mature T-lymphocytes, NK, T-cells, and some thymocytes. It 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. This MAb is particularly useful for induction of T cell activation in vitro and in vivo due to its unusual IgG3 isotype. 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.