Immunoglobulin heavy constant mu (IGHM)

Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors that, upon binding of a specific antigen, activate the clonal expansion and differentiation of B lymphocytes to immunoglobulins-secreting plasma cells.

Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:22158414, PubMed:20176268). Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen.