Immunoglobulins, also known as antibodies, are proteins produced by the immune system to help fight off infections. The word "immunoglobulins" is spelled as /ɪˌmjuːnəʊˈɡlɒbjʊlɪnz/ in IPA phonetic transcription. The first syllable is pronounced with a short "i" sound and stress is placed on the second syllable. The "b" is silent and the "g" is pronounced like a "j". The word can be broken down into "immuno-" meaning immune and "-globulins" meaning proteins in the blood.
Immunoglobulins, also known as antibodies, are specialized proteins produced by plasma cells (a type of white blood cell) as part of the immune response system in vertebrates. These glycoproteins play a crucial role in defending the body against foreign substances, such as bacteria, viruses, and toxins.
Immunoglobulins are composed of four polypeptide chains: two light chains and two heavy chains, which are held together by disulfide bonds. These chains form a Y-shaped structure with a variable region at the tip of each "arm" that recognizes and binds specific antigens. This recognition enables immunoglobulins to initiate various immune responses, including neutralization of pathogens, activation of the complement system, and recruitment of other immune cells.
There are five major classes of immunoglobulins: IgG, IgA, IgM, IgD, and IgE. IgG is the most abundant and long-lasting antibody, responsible for fighting infections and providing passive immunity to a developing fetus. IgA is mainly found in secretions, such as saliva and breast milk, protecting mucous membranes. IgM is the first antibody produced in response to an infection, while IgD remains primarily on the surface of B cells, assisting in their activation. IgE plays a crucial role in allergic reactions, triggering the release of histamine from mast cells.
Measurement of immunoglobulin levels can help diagnose certain diseases, such as allergies, immune deficiencies, and autoimmune disorders. Immunoglobulins are also utilized in medical treatments, including passive immunization to provide short-term immunity against specific diseases. Overall, immunoglobulins are fundamental in maintaining the body's immune function and protecting against a wide range of pathogens.
The word "immunoglobulins" is derived from two roots: "immuno-" and "globulin".
1. "Immuno-" is derived from the Latin word "immunis", meaning "exempt" or "free" from some obligation. In the context of immunology, it refers to the immune system's ability to defend the body against foreign substances or infectious agents.
2. "Globulin" is derived from the Latin word "globus", meaning "a ball" or "a rounded mass". In biology, it refers to a major classification of proteins characterized by their spheroidal (globular) shape.
Therefore, the term "immunoglobulins" combines these two roots to describe a group of proteins found in the immune system that are involved in immune responses, specifically related to antibody production.