(Science: immunology) An immunoglobulin M molecule (970 kD) is built up from five immunoglobulin g type monomers joined together, with the assistance of j chains, to form a cyclic pentamer.
immunoglobulin M binds complement and a single molecule bound to a cell surface can lyse that cell. Immunoglobulin M is usually produced first in an immune response before immunoglobulin g.
The human red cell isoantibodies are immunoglobulin M antibodies. Heavy chain (mu chain) is rather larger than the heavy chains of other immunoglobulins.