Micro U2 L8.

Question 1

MHC class II genes - how can it cause allergy?

Answer 1

enhanced presentation of particular allergen-derived peptides

Question 2

T-cell receptor alpha locus - how can it cause allergy?

Answer 2

enhanced T-cell recognition of certain allergen derived peptides

Question 3

TIM gene family - how can it cause allergy?

Answer 3

regulation of the Th1/Th2 balance

Question 4

IL-4 - how can it cause allergy?

Answer 4

(causes differentiation of Th2) - variation in expression

Question 5

IL-4R - how can it cause allergy?

Answer 5

increased signaling in response to IL-4

Question 6

High-affinity IgE receptor Beta chain - how can it cause allergy?

Answer 6

variation in consequences of IgE ligation by antigen

Question 7

ALOX5 - how can it cause allergy?

Answer 7

variation in leukotriene production

Question 8

Beta2Adrenergic receptor — how can it cause allergy?

Answer 8

increased bronchial hyper-reactivity

Question 9

ADAM33 - how can it cause allergy?

Answer 9

variation in airway remodeling

Question 10

What supports the hygiene hypothesis?

Answer 10

incidence of allergies has doubled over the past 10-15 years possibly due to better and increased hygiene

Question 11

How do parasite-infested populations differ from parasite-free populations?

Answer 11

no parasites - immune system does not develop in the presence of parasites and parasite-specific IgE - lose balance of tolerance/resistance causing an increased tendency for the generation of inflammatory IgE-mediated immune responses against environmental shit

Question 12

hypersensitivity reaction

Answer 12

occur after subsequent exposure to an antigen due to its interaction with previously formed antibodies or as a consequence of the activation of antigen-specific memory Tcells

Question 13

Type I hypersensitivity

Answer 13

IgE binding to its FcR on mast cells leading to their activation - immediate due to pre-formed mediators (also have late phase involving cellular infiltration)

Question 14

Type II hypersensitivity

Answer 14

IgG binding to FcR on phagocytes, NK cells, followed by complement activation or binding of IgG to a cell-surface receptor leading to altered signaling (antibody binds to proteins on human cells)

Question 15

Type III hypersensitivity

Answer 15

formation of immune complexes which bind to FcR and fix complement

Question 16

Type IV hypersensitivity

Answer 16

mediated by antigen-specific effector T cells (usually CD4 mediated that are presented by MHC class II) - 1-3 days after contact

Question 17

Examples of Type I hypersensitivity

Answer 17

allergic rhinitis, asthma, systemic anaphylaxis

Question 18

Examples of Type II hypersensitivity

Answer 18

drug allergies (esp penicillin), hemolytic anemia (destruction RBCs), thrombocytopenia (destruction of platelets), mismatched blood transfusions, autoimmune diseases including myasthenia gravis, Grave’s disease, Hashimoto’s thyroiditis, insulin-resistant diabetes

Question 19

Examples of Type III hypersensitivity

Answer 19

serum sickness, vasculitis (if in blood vessels), nephritis (renal glomeruli), arthritis (joints)

Question 20

Examples of Type IV hypersensitivity

Answer 20

contact dermatitis, chronic asthma, chronic allergic rhinitis, poison ivy, celiac disease (gluten)

Question 21

What is important in the production of Type I hypersensitivity

Answer 21

IL-4 (Th2 environment favors the development of allergies)

Question 22

What do mast cell granules contain?

Answer 22

enzymes like tryptase, toxic mediators like histamine, cytokines like TNF alpha, chemokine like CCL3, lipid activators like leukotrienes

Question 23

tryptase

Answer 23

contribute to tissue remodeling

Question 24

histamine

Answer 24

increases vascular permeability and cause smooth muscle contractions

Question 25

TNF alpha

Answer 25

promotes inflammation and stimulates other cytokine production

Question 26

CCL3

Answer 26

promotes influx of monocytes, macrophages, and neutrophils

Question 27

leukotrienes

Answer 27

cause smooth muscle contraction and increases vascular permeability

Question 28

Treatment of Type I hypersensitivity

Answer 28

1. avoidance of allergen 2. use of drugs to reduce symptoms (anti-histamines, corticosteroids, epinephrine) 3. desensitization to allergen 4. targeting effector cells and mechanisms 5. allergen peptide vaccination

Question 29

What cytokines are important for the initiation of type IV hypersensitivity

Answer 29

chemokines, IFN-gamma, TNF-alpha, IL-3, GM-CSF

Question 30

Treatment for types II, III, IV hypersensitivities

Answer 30

1. avoidance of allergen 2, reduction of the impact of immune response 3. reduce the immune response in general (steroids) 4. induce regulation of response - Treg 5. block the effector mechanisms