IgE Immunology

Question 1

Allergic reactions are Type __ hypersensitivity reactions

Answer 1

Type 1

Question 2

The ability to transfer reactivity to allergens by means of serum

Answer 2

Atopy

Question 3

IgE has binding sites for these high affinity receptors

Answer 3

Fc epsilon

Question 4

Number of Fc regions on the Fc for binding

Answer 4

2 (CH4 and CH3)

Question 5

Basophils are circulating ________

Answer 5

Leukocytes

Question 6

Major subtypes of mast cells

Answer 6

MC(T) cells (tryptase)

MC(TC) cells (tryptase and mast cell-specific chymase)

Question 7

Location of MC(T) cells

Answer 7

Mucosa of respiratory and GI tracts. Increase with inflammation

Question 8

Location of MC(TC) cells

Answer 8

Connective tissue (dermis, submucosa of GI tract, heart, conjunctivae, and perivascular tissues)

Question 9

Common component of many of the environmental antigens

Answer 9

They contain chitin-polysaccharide (not found in mammals)

Question 10

Immunodominant peptides are presented in which loci

Answer 10

Class II D MHC loci by dendritic cells, in concert with non-MHC genes

Question 11

Genetic dictation of response of child with 2 atopic parents

Answer 11

50%

Question 12

Likelihood of child with no atopic parents becoming atopic

Answer 12

15%

Question 13

Sites of tight control of IgE serum levels

Answer 13

MHC linked genes, maternal genes on chromosome 11, and others

Question 14

3 keys to developing an allergy

Answer 14

1) Exposure (high level of exposure early in life, combined with relative lack of exposure to disease antigens that elicit Th1 and Th2 responses)
2) Route (delivery to mucosal surfaces)
3) Genetic predisposition

Question 15

Cytokines that are produced in allergic reaction

Answer 15

IL-4, instead of IL-12. DC cells uptake allergen via “allergic” TLR

Question 16

Cytokine profile of allergic reaction

Answer 16

IL-4, IL-13

IL-4 is the critical signal from the Th-2 cell to an allergen specific B-cell

Question 17

These can produce IL-4, which then activate epsilon germ-line transcription in B-cells, resulting in IgE synthesis

Answer 17

Mast cells, basophils, and Th2

Question 18

Promotion of IgE class switching via up-regulation of this

Answer 18

CD23, aka Fc epsilon RII receptor

Question 19

Arming vs. activation of Fc epsilon receptors cells

Answer 19

Arming: binding to high affinity IgE Fc receptors
Activating: cross-linking the IgE previously bound to Fc epsilon R receptors by subsequent receptors.

Question 20

Signal transduction activates these subsequent steps

Answer 20

Ca2+ influx into armed mast cells/basophils

Degranulation of potent vasoactive, inflammatory, and fibrogenic mediators

Question 21

High affinity IgE Fc receptor

Answer 21

FcεRI

Question 22

Low affinity IgE Fc receptor

Answer 22

FcεRII

Question 23

This IgE Fc receptor controls B cell growth and differentiation

Answer 23

FcεRII

Question 24

This IgE Fc receptor plays a critical role in promoting degranulation and phagocytosis

Answer 24

FcεRI

Question 25

Immediate allergic reaction

Answer 25

Release of prostaglandin and leukotrienes | Direct complement activation by tryptase cleavage

Question 26

Late phase is completely dependent upon ____________

Answer 26

T-cell activation | Cytokines IL3, 4, 5, 13, TNF-alpha, CM-CSF, and IL-10

Question 27

Characteristic of late allergic reaction

Answer 27

Eosinophils, neutrophils, additional mast cells, basophils, and lymphocytes

Question 28

Role of IL-5 in late allergic reaction

Answer 28

IL-5 stimulates release of eosinophils from bone marrow, and augments effects of eotaxin Increases Fc epsilon R display

Question 29

Unique inflammatory enhancers produced by eosinophils

Answer 29

Major basic protein (also called PRG2), leukotrienes, and cationic proteins

Question 30

Skin lesions that occur when IgE armed mast cells are activated in the skin

Answer 30

Urticaria, aka hives

Question 31

Allergin binding to cells in nasal submucosa, inciting chronic allergic inflammatory reaction driven by continuous aeorallergen exposure

Answer 31

Allergic rhinitis

Question 32

IgE armed cells recruited to submucosal sites of pulmonary bronchi

Answer 32

Acute and chronic bronchial asthma

Question 33

The MOST important factor in arriving at the correct diagnosis in cases concerning allergy

Answer 33

Careful clinical history

Question 34

NOT the most important factor in arriving at the correct diagnosis in cases concerning allergy

Answer 34

Blood/skin tests

Question 35

RAST

Answer 35

Blood test with solid-phase allergen and radio-labeled anti-IgE

Question 36

These types of exposures to allergen dominate

Answer 36

Mucosal

Question 37

ONLY FcR THAT CAN BE OCCUPIED BY ANTIBODY WITHOUT ANTIGEN

Answer 37

Fc epsilon receptor

Question 38

Important type of immunotherapy

Answer 38

SLIT (sublingual immunotherapy) or SCIT (subcutaneous immunotherapy)

Question 39

Difference between angioedema and urticaria

Answer 39

Angioedema is lesion below the skin