IgM stands for immunogoblulin M. IgM (found mainly in the blood and lymph fluid) is the first antibody be made by the body to fight a new infection. IgM antibodies work to eliminate pathogens in the early stages of B-cell mediated (humoral) immunity before there is sufficient IgG. IgM is expressed on the surface of B cells (monomer) and in a secreted form (pentamer) with very high avidity (forms multiple binding sites with antigen).
What is IgM?
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