Definition of "antibody" []

• A Y-shaped protein on the surface of B cells that is secreted into the blood or lymph in response to an antigenic stimulus, such as a bacterium, virus, parasite, or transplanted organ, and that neutralizes the antigen by binding specifically to it; an immunoglobulin. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In the foregoing illustration it has been assumed that complete acquired active immunity has been conferred upon the experimental rabbit in consequence of the formation of antibody, specific to the diplococcus pneumoniac, sufficient in amount to ensure the destruction of enormous doses of the living cocci -- the _antigen_ (that is the substance injected in response to which _antibody_ has been elaborated) in this particular case being the bacterial protoplasm of the pneumococcus with its endo-toxins."
• "If your child has the hepatitis D virus infection a blood test will show the anti-delta antibody is positive for hepatitis D virus."
• "Most vaccines work in terms of stimulating something known as antibody, which is a protein substance in the body."