IGM
IgM: translation
(= macroglobulin)
An IgM molecule (970 kD) is built up from five IgG type monomers joined together, with the assistance of J chains, to form a cyclic pentamer. IgM binds complement and a single IgM molecule bound to a cell surface can lyse that cell. IgM is usually produced first in an immune response before IgG. The human red cell isoantibodies are IgM antibodies. Heavy chain ( mchain) is rather larger than the heavy chains of other immunoglobulins.