immunoglobulin
Meaning of immunoglobulin: Immunoglobulins are antibody proteins produced by immune cells to recognize and bind specific foreign targets such as bacteria, viruses, or toxins.
Definition of immunoglobulin
An immunoglobulin, also called an antibody, is a protein produced by B cells and plasma cells, specialized white blood cells that are part of the immune system. Each immunoglobulin is built from two heavy protein chains and two light protein chains arranged into a Y shaped structure, with a region that binds to a specific foreign target such as a bacterium, virus, or toxin.
The immune system produces several distinct classes of immunoglobulin, each suited to a different role, such as circulating in the blood, concentrating in mucous membranes, or triggering allergic responses. This variety allows the immune system to mount different types of response depending on where and how a foreign substance is encountered.
Because immunoglobulins are produced in response to specific foreign targets, measuring particular immunoglobulin levels or classes is used clinically to help evaluate immune function, detect past or current infection, and investigate certain autoimmune and allergic conditions.
Also known as
Used in a sentence
Laboratory testing measured the patient's immunoglobulin levels as part of the immune evaluation.
Good to know
The distinct classes of immunoglobulin serve different roles within the immune response, so measuring one class alone does not fully characterize a person's overall antibody based immune function.
Word origin
Where “immunoglobulin” comes from
Formed from Latin immunis, meaning exempt or free from burden, and globulus, meaning a small globe or sphere, describing the protein's globular shape.