In humans there are five classes of immunoglobulins (Igs), IgG, IgM, IgA, IgE and IgD, all of
which are glycoproteins. The Igs are the major secretory product of the adaptive immune
system, and they bind to antigens via variable sequences on their Fab regions. The binding
to antigen results in neutralization or agglutination of bound material and also initiates
effector functions via the Fc regions, such as opsonisation and activation of the classical
complement pathway through binding of C1q. Mannan binding lectin (MBL), the …