Teacher sheet · Ages 15–16 · about 45–50 minutes
Innate and adaptive immunity
Lesson page: echoesof.science/school/immune-system/ages-15-16/ · Pupil worksheet: echoesof.science/school/immune-system/ages-15-16/print/
Learning aims
- Distinguish innate and adaptive immunity.
- Describe phagocytosis, antigen presentation and antibody production.
- Explain primary and secondary responses and the principle of vaccination.
- Carry out and evaluate a quantitative handwashing model investigation.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: why do you rarely catch the same illness twice? |
| 10 min | Read the text; flowchart from cut to antibodies. |
| 25 min | Scrubbing-time investigation and class data pooling. |
| 5 min | Antibody graph sketch. |
| 5 min | Quiz or sorting game. |
Materials for the experiment
- Washable paint or hand cream mixed with fine biodegradable glitter
- Liquid soap, water and paper towels
- Stopwatch
- A transparent grid (1 cm squares) or a phone camera
- Results table
Safety: Use biodegradable glitter and washable paint or cream; check for skin allergies first. Keep hands away from eyes. Wipe up water to prevent slips. Results are for learning, not for judging anyone's hygiene.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| Antibodies kill germs directly like antibiotics. | Antibodies bind specific antigens and mark or block pathogens; other cells and mechanisms then destroy them. |
| Vaccines give you the disease in a mild form. | Vaccines use non-infectious antigens, giving immune memory without the disease. |
| Hot water is needed to kill germs on hands. | Warm and cold water remove the same number of germs; lather and scrubbing time matter. |
Worksheet answers
- Barriers are breached; phagocytes (neutrophils, macrophages) engulf bacteria and inflammation occurs; dendritic cells present antigens; a B cell with a matching receptor is activated (with help from helper T cells) and divides to form plasma cells that secrete specific antibodies; memory cells remain.
- Primary: lag of days, then a modest rise and fall. Secondary: shorter lag, a much higher peak (tens to hundreds of times), lasting longer.
- Example: rinse only ≈ 20% removed, 5 s ≈ 50%, 10 s ≈ 70%, 20 s ≈ 85% with ranges of ±10%; any answer that matches their data and notes the trend levels off.
- Glitter is far larger than microbes and does not grow or stick in the same way; counting specks is subjective. Improvement: more squares counted, photographs counted by two people, repeat trials, fixed soap volume.
Quiz answers
- Which of these is part of innate (non-specific) immunity? Neutrophils engulfing bacteria. Phagocytes act against any pathogen.[2]
- Where do T lymphocytes mature? In the thymus. T cells mature in the thymus; B cells in the bone marrow.[3]
- An antigen is… a molecule that stimulates an immune response. Antibodies bind specific antigens.[4]
- An antibody molecule is made of… two heavy and two light chains. The chains form a Y shape with variable antigen-binding regions.[5]
- Why is the secondary response faster and larger? Memory cells quickly become plasma cells. Memory cells give tens to hundreds-fold more antibody.[5]
- How does a vaccine give protection? It produces a primary response and memory without the disease. Non-infectious antigens train the adaptive system.[4]
Going further
Calculate the percentage of white blood cells that are not neutrophils if neutrophils are 55%. Then research why some vaccines need a booster dose.
Sources used in this lesson
- [2] Concepts of Biology, 17.2 Innate Immunity (OpenStax, Rice University): reliability High
- [3] Biology 2e, 42.1 Innate Immune Response (OpenStax, Rice University): reliability High
- [4] Concepts of Biology, 17.3 Adaptive Immunity (OpenStax, Rice University): reliability High
- [5] Biology, 42.2 Adaptive Immune Response (OpenStax, Rice University): reliability High
- [6] About Handwashing (Centers for Disease Control and Prevention (USA)): reliability High
- [7] Hand Hygiene Frequently Asked Questions (Centers for Disease Control and Prevention (USA)): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/immune-system/sources/
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