# Vaccines are used to protect individuals against communicable diseases. Explain how a vaccine causes the body to produce antibodies and describe the role of memory cells in providing long-term protection.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 5.3 Immune response · Explain · 5 marks

> Measles is a communicable disease caused by a virus. A vaccine against measles contains weakened measles virus particles. Children are vaccinated against measles as part of a routine immunisation programme.

## Mark scheme (5 marks)

1. The vaccine contains antigens (from the weakened measles virus)
2. The antigens stimulate B-lymphocytes to produce antibodies specific to the measles antigen
3. Memory cells are produced during the initial immune response to the vaccine
4. If the same measles antigen is encountered again, memory cells recognise it and respond more quickly
5. A large amount of antibodies is produced rapidly, destroying the pathogen before symptoms develop / preventing disease

## Key terms

- [memory cells](https://www.gradenine.co.uk/glossary/memory-cells)

## Related

- [Revision notes for Edexcel A-Level Biology A: Salters-Nuffield (9BN0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/vaccines-are-used-to-protect-individuals-d658a1d3) · Published by Druglandscape Ltd.