Immune System Overview Flashcards
Role of the
immune system
- Identify and neutralise pathogens.
- Distinguish self vs non-self antigens
- Distinguish pathological vs. non-harmful antigens.
- Repair the site of any injury or damage
- Tumour surveillance.
Implications of immune dysfunction
- An increased susceptibility to infection
- Increased susceptibility to autoimmunity
- Al lergies and autoimmunity (cross
- Insufficient incomplete repair, scarring. Excessive cell damage, chronic inflammation.
- An inability to effectively recognise and kill abnormal cancer cells
Immune over-reaction: Internal threat
Autoimmune condition (e.g., Hashimoto’s thyroiditis, rheumatoid arthritis, IBD, Type 1 diabetes etc.).
Immune under-reaction: Internal threat
- Cancer
- Re activated viruses (e.g., shingles)
Immune over-reaction: External threat
- Allergic reactions (e.g., food allergies, hay fever).
- Food intolerances.
Immune under-reaction: External threat
Infection (e.g., bacterial, parasite, viral, fungal.)
Innate Immune System
Inborn / non-specific defence
mechanism
External: First line of defence
Internal: Second line of defence
Innate Immune System: External
- Physical barriers: Skin, mucous membranes
- Chemical barriers:
Sebum
Sweat
Stomach acid
Tears
Mucus and SIgA
Cerumen
Tissue fluids
Vaginal bacteria
Innate Immune System: Internal
- Phagocytes:
Monocytes
Macrophages
Neutrophils
Eosinophils - Inflammatory response basophils / mast cells
- Fever
- Interferons
- Complement system
- Natural killer cells
Acquired/Adaptive Immune System
Third Line of Defence
T-Cells (cell mediated)
B-Cells (Antibody mediated)
T-helper Cells
Th1 - intracellular pathogens (viruses)
Th2 - extracellular threats (parasites)
Th17 - extracellular pathogens (allergies and autoimmune)
T-Reg - modulate and deactivate
Th1 Activating Cytokines
Il-12
Cytokines produced by Th1
CD8 T-cells: macrophages, IFN-y, TNF-a/B
Th2 activating cytokines
Il-2, 4 and 5
Cytokines produced by Th2
Il4,5 ,10, 13 B-cells (IgE), eosinophils
