Medicine & Health
What is An antibody?
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.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains an antibody.
Key things to understand
- 1Antibodies are produced by white blood cells (B cells) in response to a specific threat, called an antigen.
- 2Each antibody binds one specific target, like a key fitting one lock.
- 3They neutralize invaders directly or flag them for other immune cells to destroy.
- 4After an infection or vaccine, memory cells keep the ability to make them, giving lasting immunity.
- 5Lab-made 'monoclonal' antibodies are used as medicines for cancer, autoimmune disease, and infections.
Frequently asked questions
- 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.