Lecture 23: Allergy Flashcards

1
Q

Which lymphocytes and cytokines are very important in allergy responses

A

Th2 cells, IL-4, 5, 13

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2
Q

NB! Allergens are a diverse group of ___ and _______

A

Proteins and glycoproteins

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3
Q

Which receptors are commonly activated in allergic responses

A

PRRs

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4
Q

What plays an important role in allergens being able to cross the skin/mucosa

A

Protease activity of the allergen

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5
Q

Atopy is most easily defined as

A

The presence of a type I hypersensitivity reaction to an allergen
-Or the propensity for developing immediate hypersensitivity reactions to common environmental allergens

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6
Q

Which genes are known to be involved in predisposition to allergy

A

B chain of high affinity receptor for IgE (FceRIB)
IL-4 gene
HLA-DR genes
CD14 gene

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7
Q

What is CD14

A

It constitutes part of the receptor for bacterial LPS

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8
Q

What plays larger role in allergies- environment or genes

A

Environment

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9
Q

Hygiene hypothesis suggests what as the cause of increasing prevalence of allergy

A

Shift from Th1 to Th2 type of immunity
Decreased number/activity of Treg cells
Increased incidence of allergy is associated with decreased exposure to common infections in early life

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10
Q

Neonatal immune system shows bias towards Th1 or Th2- how do infections early in life affect this

A

Th2 - infection early in life can cause Th1 response and restore the Th1/Th2 balance
Increase in Treg cells after infections can limit the development of unrelated allergies

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11
Q

Mast cells, basophils, eosinophils- Where do each of them mature and can they be found in circulation?
Which has longest life span

A

Basophil, Eosinophil- Mature in bone marrow, Yes
Mast cell- Mature in CT, not found it circulation
Mast cells live weeks to months

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12
Q

Major development factor for mast cells, eosinophils and basophils

A

Mast cells- Stem cell factor, IL-3
Basophils- IL-3
Eosinophils- IL-5

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13
Q

Mast cell granule contents

A

Histamine, heparin sulfate and or chondroitin sulfate, proteases

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14
Q

Basophil granule contents

A

Histamine, chondroitin sulfate, proteases

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15
Q

Eosinophil granule contents

A

Major basic protein, peroxidases, hydrolases, lysophospholipase

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16
Q

Expression of FceRI on mast cell, basophils, eosinophils

A

Mast cell- High
Basophil- High
Eosinophil- Low

17
Q

Amine and lipid mediators released by mast cells and basophils cause an immediate response including

A

Vascular leakage, bronchoconstriction and intestinal hypermotility

18
Q

Allergens stimulate DCs to produce

A

IL-4

19
Q

Allergens are typically presented on Class __ MHC

A

Class II

20
Q

Th2 cells produce what cytokines after clonal expansion/activation- and they do what

A

IL-4 and IL-13

Activate B cells to become plasma cell secreting IgE

21
Q

FceRI has high affinity for

A

Fc of IgE

22
Q

What happens to IgE and FceRI structurally that ultimately leads to activation of the cell

A

Cross linking of the receptors

23
Q

Effects of histamine

A

Smooth muscle contraction, vascular permeability

24
Q

Effects of tryptase

A

Anaphylaxis, urticaria

25
Q

Effects of bradykinin

A

Vasodilator, smooth muscle contraction

26
Q

Inflammatory mediators can cause what chronic structural changes to the airway

A

Activation of tissue fibroblasts, increased collagen
Increased mucus production by goblet cells
Smooth muscle hyperplasia and hypertrophy
Increased risk of acute obstruction of airflow in lungs in response to allergens/irritants

27
Q

What cytokine(s) is/are involved in airway hyperresponsiveness

A

IL-13

28
Q

IgG blocking antibodies work how in desensitization

A

Repeat exposure to desensitizing allergen causes increased IgG Ab development, which compete with pathogenic IgE for allergen binding

29
Q

Desensitization provokes immunoregulation how

A

Exposure to repeated desensitizing allergen induces Treg cells, which recognize allergen but invoke regulatory immune responses, dampening migration, infiltration and inflammation

30
Q

Desensitization causes immune deviation- shifting from ___ to ____

A

Shifts away from Th2 and towards Th1 producing CD4 cells, increases production of IFN-y which inhibits IgE production