GCSE Biology · Edexcel 1BI0 · Topic 5C
The immune system and vaccination
Key points
- Physical barriers: skin, mucus and cilia in the airways. Chemical barriers: lysozyme in tears and hydrochloric acid in the stomach.
- Lymphocytes (white blood cells) make antibodies that fit antigens on a specific pathogen, marking it for destruction.
- After an infection, memory lymphocytes remain, so the secondary response is faster and larger: you are immune.
- Vaccination: a dead, weakened or harmless form of the pathogen triggers antibody and memory cell production without causing illness.
- Herd immunity: if most people are vaccinated, the pathogen spreads less, protecting those who cannot be vaccinated.
- Higher tier: monoclonal antibodies are made from hybridoma cells and bind to one antigen; they are used in pregnancy tests, diagnosis and to carry drugs to cancer cells.
Topic notesPremium
Your body has layers of defence: barriers that stop pathogens getting in, and an immune system that recognises and destroys those that do. This sub-topic explains how lymphocytes make antibodies, why you rarely catch the same disease twice…
Unlock the full notes with Premium
Premium includes full topic notes, the paper generator, self-quizzes and progress tracking.
Practise this topicPremium
Premium members can generate an exam-style paper with a mark scheme, or take a quick quiz, on The immune system and vaccination.