IgM Antibody [clone DA4-4, SA-DA4 or HB57] (V3130)

Description

IgM antibody (clone DA4-4, also called SA-DA4 and HB57) detects the mu heavy chain of human immunoglobulin M, the first antibody isotype produced during an immune response. Immunoglobulin M (IgM) is a pentameric glycoprotein expressed on the surface of immature B cells and secreted into plasma upon activation. The UniProt recommended name for this target is Immunoglobulin mu chain constant region. IgM serves as a key effector molecule in the primary immune response, providing early defense against pathogens through complement activation and agglutination of antigens.

Clone DA4-4 (SA-DA4, HB57) has been widely used in immunological and cell biology research for the identification and quantification of IgM-expressing B lymphocytes. The antibody specifically binds to the constant region of the IgM heavy chain and does not cross-react with other immunoglobulin classes such as IgG, IgA, IgD, or IgE. Published studies have used this clone in flow cytometry, immunofluorescence, and immunohistochemical analyses to distinguish surface IgM-positive B cells from class-switched memory subsets and plasma cells. The clone’s well-characterized specificity and reproducible performance have made it a standard reagent in immunophenotyping panels for decades.

IgM is primarily synthesized in the endoplasmic reticulum and assembled into pentamers stabilized by a joining (J) chain. The multimeric structure enhances avidity for multivalent antigens and efficiently activates the classical complement pathway via C1q binding. In plasma, IgM represents roughly 5-10% of total immunoglobulin content but is the most efficient at neutralizing pathogens early in infection. Membrane-bound IgM functions as part of the B cell receptor (BCR) complex, forming signaling assemblies with Ig-alpha (CD79A) and Ig-beta (CD79B) that initiate B cell activation upon antigen recognition.

Beyond its immune defense role, IgM contributes to homeostatic clearance of apoptotic cells, natural antibody production, and immune complex regulation. The antibody’s short half-life and large molecular size limit its diffusion into tissues, but its high avidity and complement activation capacity make it an essential mediator of early host protection. The presence of IgM antibodies is often used as a diagnostic marker of recent infection or early-stage immune activation.

IgM antibody (clone DA4-4) is suitable for detecting IgM expression on B cells, in serum, or in purified immunoglobulin samples. It provides high specificity for the mu chain and consistent results across applications that assess B cell differentiation, immune activation, or humoral response. NSJ Bioreagents provides the human IgM antibody (clone DA4-4, also called SA-DA4 and HB57) validated for use in relevant research applications, supporting studies in immunology, vaccine development, and B cell biology.

Application Notes

The optimal dilution of the IgM antibody for each application should be determined by the researcher.

1. Staining of formalin-fixed tissues requires boiling tissue sections in 10mM citrate buffer, pH 6.0, for 10-20 min followed by cooling at RT for 20 minutes.
2. The prediluted format is supplied in a dropper bottle and is optimized for use in IHC. After epitope retrieval step (if required), drip mAb solution onto the tissue section and incubate at RT for 30 min.

Immunogen

Heavy chain human IgM was used as the immunogen for this IgM antibody.

Storage

Store the IgM antibody at 2-8oC (with azide) or aliquot and store at -20oC or colder (without azide).