Lecture 19: Allergy

Question 1

an environmental Ag that elicits allergic responses in susceptible individuals. These Ags have little or no intrinsic toxicity

Answer 1

Allergen

Question 2

Clinically adverse reactions to environmental Ags mediateed by acquired immune responses

Answer 2

Allergy

Question 3

Allergies are clinically adverse reactions to environmental Ags mediated by acquired immune responses which are marked by:

Answer 3

• The presence of allergen-specific IgE
• Mast-Cells and eosinophils recruitment and/or activation
• Th2-type of responses and IL-4,IL-5, and IL-13 are key elements

Question 4

The propensity for developing immediate hypersensitivity reactions to common environmental allergens

Answer 4

Atopy

Question 5

All allergic disease have what common mechanistic aspects:

Answer 5

• All result rom harmful immune responses
• Immune responses are driven by non-infectious Ags
• Immune responses are all associated with the generation of IgE

Question 6

Allergens are a diverse group of ___ and ___

Answer 6

proteins and glycoproteins

Question 7

Allergens activate the innate immune response by:

Answer 7

• An intrinsic enzymatic activity
• Activation of PRRs

Question 8

Indoor allergens are usually associated with ____

Answer 8

asthma

Question 9

Outdoor allergens are usually associated in

Answer 9

allergic rhinitis

Question 10

Several allergnes have protease activity, which is important why?

Answer 10

may play an role in crossing skin or mucosal barriers

Question 11

Polymorphisms in what genes are known to be involved in allergic disease

Answer 11

• The ß chain of the high affinity receptor for IgE (FceRIß)
• The IL-4 gene
• The HLA-DR alleles
• the CD14

Question 12

Studies on HLA Associations show that in a North American Population IgE and IgG hypersensitivity to the ragweed Ags is associated with ____ in patients with ragweed pollen allergy

Answer 12

HLA-DR2

Question 13

CD14

Answer 13

• Main cellular expression:
  
  • Dendritic cells
  • Monocytes
  • Macrophages
  • Granulocytes
• Known or proposed function(s)
  
  • Binds complex of LPS and LPS-binding protein and Displays LPS to TLR4; required for LPS-induced macrophage activation

Question 14

High levels of ___ in the cord blood of infants predicts future development of atopy

Answer 14

IgE

Question 15

What is the hygiene hypothesis

Answer 15

• the increased incidence of allergy is associated with the decrease in exposure to common infections during early life
• infections in childhoood cause Th1-type responses and restore the Th1/Th2 balance
• Increased hygiene leads to:
  
  • Shift form Th1 to Th2 type of immunity
  • Decreased number/activity of T_reg cells

Question 16

Th2 type cells produce IL-4 and IL-13 that function to

Answer 16

• IL-4
  
  • B cells:
    
    • Isotype switching ot IgE
  • T cells:
    
    • Th2 differentiation, proliferation
  • Macrophages:
    
    • Alternative activation and inhibition of IFN-gamma-mediated classical activation
  • Mast cells: proliferation
• IL-13
  
  • B cells:
    
    • Isotype switching to IgE
  • Epithelial cells:
    
    • Increased mucus produciton
  • Fibroblasts:
    
    • increased collagen synthesis
  • Macrophages:
    
    • Alternative activation

Question 17

Crosslinking of FceRI leads to

Answer 17

activation of the cells (mast cells, basophils) and release of inflammatory mediators

Question 18

Mast cells reside in the ___

Answer 18

tissue (usually near a blood vessel)

Question 19

Basophils reside in

Answer 19

circulation

Question 20

Explain desensitization by allergen immunotherapy

Answer 20

• It compreses an induction of subcutaneous injections of increasing doses of the allergen extract, given once every 1-2 weeks
• Once the maximum dose is achieved (usualy after 6-10 weeks), maintenance injections may be required monthly for 2-3 years but may provide benefit for a further number of years

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