Lecture 24 - Allergy

Question 1

What are the main mediators of allergic response (Ab, cells, and cytokines)?

L24 S2

Answer 1

IgE

Cells:

• mast cells
• eosinophils
• Th2 cells

Cytokines (Th2 cytokines):

• IL-4
• IL-5
• IL-13

Question 2

What prompts innate immune response to allergens?

L24 S4

Answer 2

• intrinsic enzymatic activity

- PRR recognition

Question 3

What does the term atopy mean?

L24 S2

Answer 3

Propensity for developing a hypersensitivity to common environmental allergens

Question 4

Polymorphisms of what genes are associated with allergies?

L24 S10

Answer 4

• β chain of IgE receptor, FcεRIβ
• IL-4
• HLA-DR
• CD14

Question 5

What is the hygiene hypothesis and what is the proposed mechanism?

L24 S13

Answer 5

“Increased incidence of allergy is assocaited with decrease in exposure to common infections during early life”

Mechanisms:

• shift of Th1/Th2 ratio to favor Th2 (early childhood viral/intracellular bacteria infections cause Th1 responses)
• decrease in T reg cells (all infections increase number of T reg cells)

Question 6

What factors have been shown to favor Th1 phenotypes or Th2 phenotypes?

L24 S14-15

Answer 6

Th1 phenotype:

• older sibling
• daycare exposure
• rural environment
• helminth infection
• microbial (LPS) exposure

Th2 phenotype:

• only child
• urban lifestyle
• “sterile” environment
• high antibiotic use

Question 7

What is BCG and what are its potential uses?

L24 S18

Answer 7

Bacillus Calmette Guérin strain of Mycobacterium bovis

Used in vaccine for tuberculosis

Recently shown to reverse the effects of type 1 DM

Epigenetically “resets” certain T-reg genes renewing tolerance