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What is an antibody?

Medicine & HealthLesson on requestFree to read

Quick answer

An antibody is a Y-shaped protein made by the immune system that recognizes and locks onto a specific foreign invader, like a virus or bacterium. By tagging or neutralizing these threats, antibodies help the body fight infection — and remember past ones.

Key things to understand

Antibodies are produced by white blood cells (B cells) in response to a specific threat, called an antigen.
Each antibody binds one specific target, like a key fitting one lock.
They neutralize invaders directly or flag them for other immune cells to destroy.
After an infection or vaccine, memory cells keep the ability to make them, giving lasting immunity.
Lab-made 'monoclonal' antibodies are used as medicines for cancer, autoimmune disease, and infections.

People also ask

What's the difference between an antibody and an antigen?

An antigen is the foreign marker (part of a virus, say) that triggers a response; an antibody is the protein the immune system makes to bind that specific antigen.

How do vaccines create antibodies?

A vaccine shows the immune system a harmless piece of a pathogen, prompting it to make antibodies and memory cells — so the body can respond fast to the real infection.

Do antibodies last forever?

Levels often fade over time, but memory cells can quickly ramp production back up on re-exposure. How long protection lasts varies by disease.

What are antibodies?

Proteins the immune system makes to recognize and neutralize specific germs like viruses and bacteria.

How do antibodies work?

Each locks onto a specific target on an invader, neutralizing it and marking it for the immune system to destroy.

How do vaccines relate to antibodies?

Vaccines train the body to make antibodies against a germ, so it can respond fast to a real infection.