Anti-Human IgM (SAG3)

IgG is the most abundant immunoglobulin class, and IgG3 represents about 4% of total serum IgG. IgG3 is notable for its strong complement activation, high affinity for Fcγ receptors, limited placental transfer compared with other subclasses, and a relatively short half-life of around seven days. Reduced IgG3 levels are sometimes found in adults with recurrent respiratory infections.

IgM is the first antibody produced in a primary immune response and circulates mainly as a high-avidity pentamer. It efficiently activates the classical complement pathway and is also expressed on naïve B cells as part of the B-cell receptor. Anti-human IgM monoclonal antibodies specifically recognize the μ heavy chain and are widely used in flow cytometry and immunofluorescence to identify IgM+ B cells in studies of B-cell maturation, immune function, and related disorders.