# Antibody

A protein made by white blood cells that locks onto a particular pathogen and helps destroy it.

Biology (school) · Part 04: Health and disease · Card 5 of 10 · Last updated 2026-10-19

## Analogy

A custom-fit handcuff for one specific criminal.

## In practice

Each antibody matches only one type of antigen, the marker on a pathogen's surface.

## Practice

### Flashcards

- **What does an antibody do?** It locks onto an antigen on a pathogen and helps destroy it.

### Interview questions

**Explain how a vaccine gives protection against a disease.**

- A vaccine contains a dead or weakened pathogen or its antigens
- White blood cells make antibodies against the antigens
- Memory cells stay in the body
- A later infection is destroyed quickly before symptoms develop

## Questions people ask

### Why does each antibody only work on one pathogen?

An antibody has a specific shape that fits only one antigen, in the same way a key fits one lock. Different pathogens have different antigens. So the body must make a new antibody for each new pathogen it meets, which takes a few days the first time.

### What are memory cells?

After an infection, some white blood cells stay in the body as memory cells. If the same pathogen returns, they recognise it straight away and make antibodies much faster and in greater numbers. This is why you rarely catch some diseases twice and why vaccines work.

## Related concepts

- [Immune system](https://studyvisually.com/learn/science/biology-school/biology-school-part-4/biology-school-part-4-concept-4)
- [Vaccination](https://studyvisually.com/learn/science/biology-school/biology-school-part-4/biology-school-part-4-concept-6)
- [Herd immunity](https://studyvisually.com/learn/science/biology-school/biology-school-part-4/biology-school-part-4-concept-7)

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