Resp Immunology

Question 1

What components are involved with IgE production?

Answer 1

Th2 - cell activation
IL4/13 - stimulate antigen specific B cell switching to IgE
INF-G inhibits this responce

Question 2

What receptor does IgE bind on mast cells?

Answer 2

Fc (e)

Question 3

What is degranulated from IgE within seconds, minutes and hours?

Answer 3

Seconds - histamine, eosinphils, heparin, neutrophils
Minutes - leukotrienes, prostaglandins, thromboxane
Hours - cytokines

Question 4

Outline first and second allergen exposure?

Answer 4

1st - allergen specific Th2 cell activation, B cell swith and synthesis of IgE
2nd - inflammatory cell recruitment, mediator release, smooth muscle contraction, promotion of vascular permeability, mucus secretion

Question 5

Role of 5 mast cell mediators?

Answer 5

1. Histamine - bv dilation, increased permeability, sm contraction
2. Proteases - damage local tissue
3. Arachidonic acids - vascular dilation (prostaglandins)
4. Leukotrienes - sm. contraction
5. Cytokines - local inflammation

Question 6

Asthma pathogenesis: outline the two major stages?

Answer 6

1. Inflammation - allergen mediated response with epithelium defective as allergens get betwee tight junctions and
   1a. infiltrate cells. Eosinophils and CD4 cells infiltrate the airway and Th2 secretes IL3,5 (eosinophils), IL4,6,9,13 (mast cells and IgE)
   1b. change in resident cells
   1c. changes in non-cellular component of wall causing direct damage to bronchial tissue
2. Remodelling of angiogenesis, sm proliferation, basement membrane thickening, cellular inflitrates, fibrosis and increased mucus
   ALL LEADING TO AIRFLOW LIMITATIONS by chronic mucus plug and airway remodelling

Question 7

Outline how immunotherapy works?

Answer 7

APCs activate Treg cells
Treg cells release chemicals to block, suppress and eliminate Th2 cells as well as influencing B cells to switch to plasma cells and not IgE
Less IgE means less responsiveness but also more IgG4 blocking antibodies which recognize and bind allergen, preventing it from binding to IgE meaning no allergic reaction is triggered