antibody

American  

[an-ti-bod-ee] / ˈæn tɪˌbɒd i /

noun

antibodies plural

1. any of numerous Y -shaped protein molecules produced by B cells as a primary immune defense, each molecule and its clones having a unique binding site that can combine with the complementary site of a foreign antigen, as on a virus or bacterium, thereby disabling the antigen and signaling other immune defenses. Ab

2. antibodies of a particular type collectively.

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antibody British  

/ ˈæntɪˌbɒdɪ /

noun

1. any of various proteins produced in the blood in response to the presence of an antigen. By becoming attached to antigens on infectious organisms antibodies can render them harmless or cause them to be destroyed See also immunoglobulin

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antibody Scientific  

/ ăn′tĭ-bŏd′ē /

1. 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.

2. Also called immunoglobulin

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Closer Look

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.

Other Word Forms

Noun Inflected Forms

• antibodies
  plural

Etymology

Origin of antibody

First recorded in 1895–1900; anti- + body

Compare meaning

How does antibody compare to similar and commonly confused words? Explore the most common comparisons:

• antigen vs. antibody

Explanation

An antibody is a protein made by the body that latches onto foreign bacteria and viruses to make them ineffective. Each antibody is designed to target a particular opponent. A powerful part of the body’s immune system, an antibody is produced when the body senses an invader — called an antigen that it doesn’t think should be there. The body then sends out the antibody to neutralize it. Don’t think of an antibody as being anti or “against” your body; think of the body in the word antibody as the antigen, or foreign body that is being fought. Known antibodies have been especially useful in the creation of vaccines.

Example Sentences

See Examples For:

antibody antibodies

In happier news, rising case counts have jump-started research into drugs that could treat people who do get sick, including antibody and antiviral therapies.

From Slate ● Jul. 24, 2026

Because the antibody is made entirely from human proteins, it has properties that make it suitable for development as a therapeutic drug.

From Science Daily ● Jul. 21, 2026

J&J on Monday said Firefly is developing its proprietary Firelink degrader antibody conjugate platform, for KRAS-driven cancers, which have limited treatment options with survival measured in months.

From The Wall Street Journal ● Jun. 8, 2026

Roche’s anti-amyloid antibody trontinemab has a fragment that mimics the natural iron-shuttling molecule known as transferrin.

From Barron's ● Jun. 3, 2026

If there are conflicts with your original brain tissue...signals that might create almost an antibody effect...one trying to override the other...that’s why we have backups.

From "The Adoration of Jenna Fox" by Mary E. Pearson

The fever is not harmful, but it can make babies feel crummy as their body is building up antibodies against viruses and bacteria.

From Los Angeles Times ● Jul. 28, 2026

"The average Brazilian did not have antibodies against betting," he said.

From Barron's ● Jul. 17, 2026

In regions with large populations of lone-star ticks, up to 30% of people tested will have allergic antibodies to alpha-gal, but only 2% will develop an allergy, studies have found.

From The Wall Street Journal ● Jun. 25, 2026

But in lupus, and other autoimmune diseases, the B cells go rogue and produce antibodies that can attack the body.

From BBC ● Jun. 11, 2026

But sometimes it can spin out of control and produce antibodies that attack the body itself.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel

Related Words

• bacterium
• bug
• disease
• microbe
• microorganism
• pathogen
• virus