Immunoglobulin

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Immunoglobulin (also known as Ig) is a type of protein produced by plasma cells and other lymphocytes. Certain types of immunoglobulins are also known as antibodies. Immunoglobulins play a key role in the immune system by recognizing and binding to specific antigens, such as bacteria or viruses, and aiding in their destruction.

Types of Immunoglobulins[edit | edit source]

There are five classes of immunoglobulins, each with a different role in the immune response. These include:

  • Immunoglobulin G (IgG): This is the most common type of immunoglobulin. It protects against bacterial and viral infections.
  • Immunoglobulin A (IgA): Found in high concentrations in the mucous membranes, particularly those lining the respiratory passages and gastrointestinal tract, as well as in saliva and tears.
  • Immunoglobulin M (IgM): The first immunoglobulin produced in response to an infection. It also causes other immune system cells to destroy the pathogen.
  • Immunoglobulin E (IgE): Binds to allergens and triggers histamine release from mast cells and basophils, and is involved in allergy.
  • Immunoglobulin D (IgD): Functions mainly as an antigen receptor on B cells that have not been exposed to antigens.

Function of Immunoglobulins[edit | edit source]

Immunoglobulins have two primary functions:

  • Antigen binding: Immunoglobulins recognize specific antigens and bind to them. This binding can neutralize the antigen or make it easier for other cells of the immune system to destroy the antigen.
  • Effector function: After binding to an antigen, the Fc region of the immunoglobulin can interact with immune cells and complement proteins, triggering a range of immune responses.

Clinical Significance[edit | edit source]

Immunoglobulins are crucial for our body's defence against microorganisms. Abnormal immunoglobulin levels can be a sign of a health problem. These may include:

  • Immunodeficiency: Lower than normal levels of immunoglobulins can lead to repeated infections.
  • Autoimmune diseases: In some cases, immunoglobulins might mistakenly target the body's own cells, causing an autoimmune disease.
  • Allergies: High levels of a specific type of immunoglobulin known as IgE might indicate an allergy.
  • Cancers: Certain cancers, such as multiple myeloma, can cause a spike in the levels of a specific type of immunoglobulin.
Immunoglobulin Resources
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