Changes

[[Image:LH IgM.png|thumb|150px|right|'''IgM'''<p>1 = IgM monomer</p><p>2 = Heavy chains</p><p>3 = Light chains</p><p>4 =J chain</p><p>5 = Disulfide bonds</p>]]

[[Image:LH IgM.png|thumb|150px|right|'''IgM'''<p>1 = IgM monomer</p><p>2 = Heavy chains</p><p>3 = Light chains</p><p>4 =J chain</p><p>5 = Disulfide bonds</p>]]

[[Image:IgM.jpg|thumb|right|150px|IgM - B. Catchpole, RVC 2008]]

[[Image:IgM.jpg|thumb|right|150px|IgM - B. Catchpole, RVC 2008]]

<p>Is found in high concentrations in blood plasma (below IgG conc.) and is the major Ig produced during primary immune response</p>

<p>Is found in high concentrations in blood plasma (below [[IgG]] conc.) and is the major Ig produced during primary immune response</p>

==Structure==

==Structure==

<p>IgM is the primordial antibody and, although a monomer, is secreted as a pentamer (five monomers joined by disulphide bonds with two monomers joined by a J chain). This gives it ten identical antigen binding sites although IgM usually has relatively low affinity for its antigen. It heavy chain is type mu (µ ).</p>

<p>IgM is the primordial antibody and, although a monomer, is secreted as a pentamer (five monomers joined by disulphide bonds with two monomers joined by a J chain). This gives it ten identical antigen binding sites although IgM usually has relatively low affinity for its antigen. It heavy chain is type mu (µ ).</p>