What is "immunoglobulin m"

immunoglobulin \im`mu*no*glob"ulin\ ([i^]m`m[-u]*n[-o]*gl[o^]b"[-u]*l[i^]n) n. (1953) any one of a class of globular proteins which are antibodies and are produced by the immune system in animals.

Note: The immunoglobulins form a series of related proteins which are each composed of two pairs of polypeptide chains, called heavy (H) and light (L, meaning of lower molecular weight), all linked together by disulfide bonds. They are subdivided on the basis of the structural and antigenic properties of the H chains into four subgroups, immunoglobulin G (IgG), immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin D (IgD). They are divided also into subclasses. Both H and L chains of anny given class and subclass have regions which are of constant structure within that class, as well as regions which are of variable structure. The variable regions impart the ability to recognize and bind to specific molecular structures, thus providing the organism the capacity to recognize and defend itself against the harmful effects of substances foreign to the body.
--Stedman

Syn: Ig.

n. one of the five major classes of immunoglobulins; involved in fighting blood infections and in triggering production of immunoglobulin G [syn: IgM]

Immunoglobulin M, or IgM for short, is a basic antibody that is produced by B cells. IgM is by far the physically largest antibody in the human circulatory system. It is the first antibody to appear in response to initial exposure to an antigen. The spleen, where plasmablasts responsible for antibody production reside, is the major site of specific IgM production.