02 · Tissue alarm to type 2 ecology
Move from airway barrier sensing to IL-33, mast-cell activation, and the wider type 2 immune pattern.
Educational illustration · not microscopyVisual specimen
The air-facing mucus and cilia layer sits above a joined epithelial sheet and a quieter immune tissue compartment.
Look for
Conceptual tissue cutaway, not histology. Cell proportions, density, and spacing are simplified and not to scale.
OpenAI-generated educational illustration under Atlas editorial direction · 2026-07-12
Question to carry
How do tissue signals recruit and amplify an immune response instead of acting as isolated molecules?
Who this is for
A systems-immunology pathway for learners who want to connect tissue, signals, cells, and pattern.
Your journey progress
0 of 4 stops opened.
Progress stays in this browser. Atlas records only deduplicated aggregate counters with no identifiers, free text, search terms, or patient data.
Follow the route
Begin in the tissue
Start with barrier function, mucociliary clearance, resident cells, nerves, and environmental sensing in one spatial immune niche.
Boundary: The lung page describes a biologic ecosystem, not a person-specific airway state.
Follow the alarm
See how an epithelial or stromal alarm signal can lower activation thresholds and organize downstream type 2 behavior.
Boundary: A cytokine relationship shows plausible biology; it does not imply a measured cytokine level.
Inspect the amplifier
Trace how resident mast cells receive IgE, alarmin, complement, and neuroimmune context and produce rapid or sustained outputs.
Boundary: Multiple inputs can converge on similar symptoms, so mechanism requires context.
Zoom out to the pattern
Connect IL-4, IL-5, IL-13, IgE, eosinophils, mast cells, barrier tissues, and regulatory restraints as a dynamic pattern.
Boundary: A type 2 pattern is an educational lens, not a diagnosis or a treatment selector.
What to take away
Barrier tissues actively sense and shape immune responses.
IL-33 is one signal inside a larger tissue and cellular network.
Type 2 immunity includes defense, repair, allergy, regulation, and tissue remodeling context.
Educational boundary
This journey is educational and teaches a general mechanism. It does not identify the cause of symptoms, distinguish emergencies, or recommend medication, testing, or treatment.
Evidence record
Reviewed 2026-07-12 · Atlas editorial baseline
Owner Mark Pruitt · next review 2026-10-12 · stale on 2026-11-12
Source anchors
Known uncertainty
Barrier signaling varies by tissue, trigger, timing, host state, and treatment context.
The pathway is deliberately simplified so the relationships remain legible.
Atlas Professional
Approved users can inspect the allergen response trace and organize competing pattern hypotheses in Atlas Professional.