anti-body

Science Dictionary
antibody   (ān'tĭ-bŏd'ē)  Pronunciation Key 


(click for larger image in new window)

Any of numerous proteins produced by B lymphocytes in response to the presence of specific foreign antigens, including microorganisms and toxins. Antibodies consist of two pairs of polypeptide chains, called heavy chains and light chains, that are arranged in a Y-shape. The two tips of the Y are the regions that bind to antigens and deactivate them. Also called immunoglobulin.

Our Living Language  : Like other vertebrates, humans possess an effective immune system that uses antibodies to fight bacteria, viruses, and cancer cells. Antibodies are complex, Y-shaped protein molecules. The immune system's B lymphocytes, which are produced by the bone marrow, develop into plasma cells that can generate a huge variety of antibodies, each one capable of combining with and destroying an antigen, a foreign molecule. Antibodies react to very specific characteristics of different antigens, binding them to the top ends of their Y formation. Once the antibody and antigen combine, the antibodies deactivate the antigen or lead it to macrophages(a kind of white blood cell) that ingest and destroy it. High numbers of a particular antibody may persist for months after an invasion, eventually diminishing. However, the B cells can quickly manufacture more of the same antibody if exposure to the antigen recurs. Vaccines work by "training" B cells to recognize and react quickly to potential disease molecules.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Explore Dictionary.com
Previous Definition: anti-biotic
Next Definition: anti-carcinogen
Words Near: anti-body
More from Thesaurus.com
Synonyms and Antonyms for anti-body
More from Reference.com
Search for articles containing anti-body
More from Dictionary.com Translator
Dictionary.com Word FAQs

Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.

Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature