Human IgM (immunoglobulin M) is expressed on the surface of immature and mature B cells as monomers. IgM is the third most abundant human immunoglobulin.
IgM is also the first human immunoglobulin to be made by a fetus and virgin B cells which are challenged with antigen.
IgM is a strong complement activator and agglutinator due to its pentameric structure and binds fragment crystallization (Fc) receptors.
IgM |
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Heavy chain |
μ |
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Light chain |
κ or λ |
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Molecular formula |
(μ2κ2)5 or (μ2λ2)5 |
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Valency |
10 |
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Structure |
Pentamer |
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Abundance in serum (in relation to total immunoglobulins present) |
6% |
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Carbohydrate content |
12% |
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Concentration in serum |
0.5 - 2.0 mg/ml |
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IgM subclasses |
None |
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Heavy chain MW (kDa) |
70 |
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Light chain MW (kDa) |
23 |
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Total MW (kDa) |
970 |
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Distribution |
Mainly intravascular |
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Function |
Primary response antibody |
Bio-Rad offers a range of human immunoglobulin antibodies for the IgM isotype. In addition to human, we also offer IgM antibodies for a wide range of other target species. Below you will find a list of all of our IgM antibodies. Use the buttons/filters to identify the antibody that fits your exact requirements.
Description | Target | Format | Clone | Applications | Citations | Code |
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For a full overview of Immunoglobulin classes please visit our Immunoglobulins Classes / Sub-classes page. Alternatively you can view the following individual types: