The Structure of Antibodies 1959 – A Step Toward Understanding Immune Mechanisms

In the 1840s, the germ theory of disease proposed that microorganisms cause many diseases. This increased curiosity about how the body's defenses work.

Today, we know more about the body's defenses and the immune system involved in them.  

Antibodies (also called immunoglobulins) are protective proteins that identify and neutralize foreign substances called antigens, such as bacteria, viruses, parasites, transplanted foreign tissue or poisons. 

• Antibodies are produced by plasma B cells (a type of white blood cell). 
• Each antibody consists of two heavy chains and two light chains made of amino acids. These four chains join to form a molecule resembling the letter Y. 
• Variable regions at the two upper tips of the Y bind to antigens and mark them for destruction by other parts of the immune system. 
• Antibodies can prevent pathogens from entering and damaging cells. 
• They can also neutralize antigens by binding directly to them.

Fluid-based immunity or humoral immunity forms part of the body's 3rd line of defense. Antibodies in the bloodstream contribute to the humoral immune system.

By binding to an invader, antibodies mark it for engulfment by phagocytes. Phagocytes act like single-celled organisms that engulf and destroy smaller particles.

The presence of specific antibodies is used in the diagnosis of certain diseases. 

Autoimmune disorders occur when antibodies attack the body's own healthy cells. 

Antisera are produced by injecting an antigen into an animal and isolating antibodies from its serum for use in humans.

In 1891, Paul Ehrlich coined the word Antikörper (German for antibody) and proposed a mechanism in which cellular receptors bind toxins with a tight lock-and-key fit. Through independent research beginning in 1959, the British biochemist Rodney Porter and the American biologist Gerald Edelman identified the antibody's Y shape and heavy and light chains, winning the 1972 Nobel Prize.

About the Article Image: The structure of an antibody

Historical Figures Mentioned in the Article: Paul Ehrlich (1854–1915), Rodney Robert Porter (1917–1985), Gerald Maurice Edelman (b. 1929)

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