Recognizes a protein of 33-55 kDa, identified as CD37 (Workshop V; Code CD37.7). CD37 is strongly expressed on normal and neoplastic mature (sIg ) B-lymphocytes. In B-cell ontogeny, CD37 appears after the pre-B-cell stage, is maintained during peripheral B-cell development and is lost upon terminal differentiation into plasma cells.1 CD37 is also present, at low densities, on resting and activated T cells, neutrophils, monocytes, and some myelomonocytic leukemia cells. It is absent from platelets, erythrocytes. CD37 is a member of a family of tetraspan transmembrane proteins, including CD9, CD53, CD63, CD81, and CD82. It associates other tetraspan transmembrane proteins and MHC class II molecules to form a large complex at the surface of B cells and play a role in signal transduction. CD37 is a valuable and stable marker for peripheral mature B-cells and corresponding malignancies like B-cell chronic lymphocytic leukemia (B-CLL), hairy cell leukemia (HCL), and all types of B-cell non-Hodgkin” lymphoma (B-NHL).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.