Wk16 Lab report: Immune system modeling

H1: what you will build

Build an original paper model, then save a comparison diagram and model notes together. You will show matching, a first response, a repeat response and one way binding can block viral entry.

Use plain paper and a pencil. You may sketch every part without cutting or sharing materials. If using teacher-provided cards, confirm their rules first. Keep those records separate if their rules differ.

No microbes, body samples, medicines or health histories are needed. Use classroom directions for any shared tools. Do not conduct an infection test. A paper run cannot establish a person’s immune status.

E1: recognition and cell roles

MedlinePlus describes the immune system as a network of cells, tissues and organs working in defense. Use that fact to explain why antibody matching represents only part of the whole response.

A pathogen may carry many antigens. An antibody contacts an epitope, a particular part of an antigen. Its binding site has features that fit that target. Shape helps explain this fit, but real binding also depends on chemical interactions.

A B cell already has receptors before it meets a target. The encounter selects cells able to respond. With the needed signals, activated cells expand. Some become plasma cells that release antibodies; some become memory cells. Helper T cells support many of these responses.

An antibody is a protein, not a cell that learns or remembers. Memory B cells can later help produce plasma cells and antibodies. A single antibody can sometimes bind related targets. Specificity does not mean one rigid key fits only one possible germ.

E2: binding, blocking and memory

Binding and neutralization are different claims. An antibody can block infection if it prevents a virus from using a needed entry feature. Binding elsewhere may not block entry. Other immune actions can still matter.

A first response often needs days while selected cells expand and become plasma cells. A repeat encounter with the same target can lead to a quicker, stronger response. Innate and adaptive defenses can overlap.

Vaccination can prepare an immune response before a later encounter with a pathogen. Protection varies with the vaccine, the target and the person. Memory does not promise lifelong protection, zero illness or a milder second infection in every case.

Our model shortens the cell steps and uses a simple fit rule. Its clock and antibody levels are invented teaching units. They are not measurements, a clinical cutoff or a forecast of recovery.

S1: complete original shape model

On paper, draw a large circle labeled virus A. Add one triangle tab on its edge and label that tab entry epitope A. Draw virus B as another circle with a square tab labeled epitope B.

Draw a Y labeled antibody A. At both tips, draw a triangle-shaped hollow and label each binding site. Draw a second Y with square hollows and label it antibody B. Size each hollow to fit its matching tab in your sketch.

Draw a host-cell edge with a triangle hollow labeled entry receptor. In this model, A’s triangle can reach that receptor when uncovered. Draw antibody A covering the triangle: the covered tab cannot contact the receptor. Label this blocking step neutralization in this model.

Use this exact model rule: triangle fits triangle hollow; square fits square hollow; triangle and square do not fit. Test and record antibody A with A, antibody A with B, and antibody B with B. The shape names work without color.

Before testing, predict the three matches and give a reason. Sketch a matched pair and a mismatch. These are checks of the stated paper rule, not molecular binding experiments. Do not generalize this binary rule to every real antibody.

Draw one box labeled responding B cell, one labeled plasma cells and one labeled memory B cells. Connect responding B cell to plasma cells and memory B cells. Connect plasma cells to antibodies. These arrows show cell development or release, not fluid flow.

D1: two complete model runs

The table below is a rule sheet, not observed data. In each run, introduce virus A at model tick 0. Keep the same paper shapes, fit rule and tick spacing. The repeat run starts with memory B cells already marked.

Draw a seven-row record with columns model tick, first-run antibody tokens, repeat-run antibody tokens and process note. Copy ticks 0, 1, 2, 3, 4, 5 and 6. Leave your result columns blank until you run each sequence.

Rule table for ticks 0 through 6: first-run antibody-token levels are 0, 0, 0, 1, 2, 3 and 2. Repeat-run levels are 0, 2, 4, 6, 5, 4 and 3. Each number is the total at that tick, not an amount to add.

First run: mark the B-cell box at tick 0. At ticks 1 and 2, mark activation and expansion. At tick 3, mark plasma cells and place one antibody token. Follow the remaining totals, then mark memory B cells available for a later encounter.

Before the repeat run, reset the displayed antibody tokens to zero but keep the memory-cell mark. This deliberate simplification isolates the memory route; real antibodies can remain between encounters. The gap between encounters is unspecified.

Repeat run: reintroduce A at tick 0. At tick 1, mark memory-cell activation leading to plasma cells and set two tokens. Follow the remaining totals. Explain that these prescribed rules, not an experiment, create the faster model response.

At each tick, draw or move tally marks until they equal the stated total. Record the total and process note. If you lose your place, redo that tick and label the correction. Do not label a copied rule table as a performed run.

Compare the first tick with at least one token in each run. Subtract the repeat-run tick from the first-run tick. Report the difference in model ticks. This threshold is only a comparison rule, not an immune-protection threshold.

For the comparison diagram, use two panels with the same scales. Label each horizontal axis time since exposure, model ticks 0–6. Label each vertical axis antibody level, model tokens 0–6. Plot all seven points in each panel and join neighboring points to show the model sequence.

Label first exposure and repeat exposure at their own tick 0. Add a legend and mark where the memory route is used. Write: no conversion to real days or antibody concentration. A line between points guides the eye; it does not supply new measurements.

E3: a real example and the extension

CDC explains that flu viruses change over time. Some changes affect surface antigens. Antibodies against one virus can still recognize a related virus with similar antigen features. Larger or strategically placed changes can reduce recognition and protection.

Flu vaccine composition is reviewed each year and updated as needed. A mutation does not automatically make every antibody useless or force a new vaccine. The effect depends on what changed and how immune responses recognize it.

For an optional extension, imagine that A’s entry epitope changes. Case X says existing antibodies still bind it. Case Y says binding is reduced. Explain why these cases allow different predictions. Name the binding and neutralization evidence needed before claiming lost protection.

C1: self-check and independent exchange

Check: both A and B are present under S1’s exact rules. You have antibody A. Predict which target binds. Explain which model entry step could be blocked, why this helps explain vaccine specificity, and one limit of the analogy.

After your answer, check the reasoning against S1’s exact fit rule: compare antibody A’s shape with each target, then name the entry tab a fitting antibody would cover. Vaccines can prepare target-related responses. The model does not prove universal one-target binding or guaranteed protection.

Work with a partner only if available. Ask: Does binding prove neutralization? Record the actual answer, then improve your explanation. Working alone, critique this supplied claim: Every antibody that binds also blocks infection. Use E2 and revise the claim.

If you need a smaller start, sketch antibody A and epitope A. Label their fit, then label a B cell and a plasma cell. Return to both full runs, all diagram points and the neutralization note. The smaller start does not replace the product.

P1: your assigned work and next lesson

For May 3, prepare Innate and adaptive immunity for 25 minutes in Class Records. Define antigen, antibody and B cell, and explain one limit of the shape analogy. Keep this preparation separate from the 80-minute lesson.

Ask your teacher which Lesson 3.2 simulation or Activity 3.2.2 modeling task is assigned. Confirm the activity, partner directions and required materials. Complete that assigned work when available; today’s original model does not complete it automatically.

Activity 3.2.2 Immune Defense includes cell research, comparisons of bacterial and viral responses, teacher-led origami demonstrations and a ten-term concept map. Obtain the assigned video, model tours, template, full build directions and Amazon Travel Journal pages 7–8 before that work.

Keep any assigned 3.2.1 organizer, seven-structure model and journal pages 1–2 on your checklist. Do not mark a prior immunity task done because you read its lesson. Save the requested note or screenshot only after genuine assigned completion.

The May 3–7 checklist includes evidence through 3.2.3 Going Un-Viral and an Immune defense model. It also lists vaccine-data CER, transmission, a plaque assay and eye dissection. Obtain the teacher packet and assigned Khan resources for absent work.

Ask your teacher whether any debate work is assigned this week and which remaining tasks apply. Keep any confirmed debate or later practical work separate; this model performs neither.

Tomorrow, May 4, bring this diagram and your model notes for antibody-data analysis and CER. Obtain the actual assigned data before making claims about it. Do not turn today’s model ticks or tokens into actual vaccine results.

Use the original model, official task, preparation, tracker and submission checks to identify a specific next action; describe only work you actually do. Name missing materials or access when needed. Do not invent a partner answer, measured value or upload.

Predict before running

Write two predictions: how fit affects recognition, and what remains after a first response. Then predict S1’s three pair results before testing.

Use E1 and S1. Treat the key analogy as a starting model, not an absolute rule.

Build and test the paper model

Make the S1 shapes and labeled cell boxes. Record all three matches, the matching pair and the mismatch. Include one MedlinePlus E1 fact about the whole immune system.

Pencil sketches are enough. Label binding sites and epitopes; show B-cell development and antibody release with arrows.

Run first exposure

Run all seven first-exposure ticks in D1. Record totals, process notes and any corrections.

Use total tokens, not cumulative addition. Separate your prediction, actual paper action and interpretation.

Run repeat exposure

Reset as directed, retain the memory-cell mark and run all seven repeat-exposure ticks. Compare first nonzero ticks and calculate the difference.

Keep model ticks as the unit. Explain the reset assumption and why these rules cannot measure real response speed.

Show neutralization

Draw A before and after antibody A covers its entry tab. Explain why the covered tab cannot reach the modeled host receptor. Contrast this with M1.

Binding is shown by fit; blocking is shown by loss of receptor contact. Do not claim all bound antibodies neutralize.

Make the comparison diagram

Plot both D1 runs in two panels using identical 0–6 scales. Include all fourteen points, level/time labels, legend, exposure marks and the memory-route note.

Use M1 for the method, not its numbers. Add both the no-real-time conversion limit and the arbitrary-level limit.

Explain, check and revise

Answer every part of C1’s A/B check. Complete the real partner exchange or supplied solo critique. Revisit the two opening predictions with evidence.

Explain vaccine preparation using E2. The one-token comparison does not establish protection.

Optional changed-target extension

After core work, compare E3 Cases X and Y. Explain what is known and what must be tested before claiming a vaccine update is needed.

Use the CDC fact about annual review and updates as needed. Do not treat every mutation as loss of all recognition.

Finish the report and check your next step

Keep diagram, three fit checks, both run records, calculation and neutralization notes in the same lab report. Use P1 to identify what you checked and anything you need; bring the work tomorrow.

If absent, complete the full paper route. Ask for missing official materials or access. After uploading, check that Schoology shows Submitted.