Mouse Anti-IGHM Recombinant Antibody (SPM188) (CBMAB-I1091-YY)

Immunoglobulin Heavy Constant Mu

The IGHM gene encodes the C region of the mu heavy chain, which defines the IgM isotype.

MU; VH; AGM1

Constant region of immunoglobulin heavy chains. 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 which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into 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).

The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen (PubMed:17576170, PubMed:20176268).

IgM antibodies play an important role in primary defense mechanisms. They have been shown to be involved in early recognition of external invaders like bacteria and viruses, cellular waste and modified self, as well as in recognition and elimination of precancerous and cancerous lesions. The membrane-bound form is found in the majority of normal B-cells alongside with IgD. Membrane-bound IgM induces the phosphorylation of CD79A and CD79B by the Src family of protein tyrosine kinases. It may cause death of cells by apoptosis. It is also found in soluble form, which represents about 30% of the total serum immunoglobulins where it is found almost exclusively as a homopentamer. After the antigen binds to the B-cell receptor, the secreted form is secreted in large amounts (PubMed:3137579, PubMed:16895553).

Adaptive immune response Source: UniProtKB
Antibacterial humoral response Source: UniProtKB
B cell receptor signaling pathway Source: GO_Central
Complement activation, classical pathway Source: GO_Central
Defense response to bacterium Source: GO_Central
Defense response to Gram-negative bacterium Source: UniProtKB
Innate immune response Source: UniProtKB
Phagocytosis, engulfment Source: GO_Central
Phagocytosis, recognition Source: GO_Central
Positive regulation of B cell activation Source: GO_Central

Isoform 1: Secreted. During differentiation, B-lymphocytes switch from expression of membrane-bound IgM to secretion of IgM.
Isoform 2: Cell membrane

Agammaglobulinemia 1, autosomal recessive (AGM1):
A primary immunodeficiency characterized by profoundly low or absent serum antibodies and low or absent circulating B cells due to an early block of B-cell development. Affected individuals develop severe infections in the first years of life.