Type I Hypersensitivity

Question 1

Type 1 hypersensitivity

Answer 1

• humoral immune respone
• allergies or asthma
• exaggerated Th2 response
• Excessive amount of IgE=Atopy
• affected animals=atopic
• genes + envir. factors = allergies
• susceptible breeds
• human child infection
• early contact w/ allergens
• intestinal microflora, parasite worms

Question 2

Overproduction of which antibody?

Answer 2

IgE

Question 3

IL-4 overproduction, therefore

Answer 3

increase Th2 activation & B cell stimulation

Question 4

FceR has ___ affinity & ___ binding

Answer 4

increased & irreversible binding

Question 5

Where is FceRI present?

Answer 5

Mast cells, basophils, neutrophils, eosinophils, macrophages & dendritic cells

Question 6

Where is FceRII present?

Answer 6

B cells, NK cells, macrophages, dendritic cells, eosinophils & platelets

Question 7

3 main components

Answer 7

IgE, Mast Cell & antigen/allergen

Question 8

Is there a rxn seen after first exposure?

Answer 8

no

Question 9

The allergy loop dendritic cells express trimeric FceRI and as a result can bind antigen-

Answer 9

IgE complexes.

-stimulates Th2 –> secrete cytokines

Question 10

FceRI

Answer 10

• high affinity
• mast cell degranulation
• eosinophil ADCC
• dendritic cells
• macrophages

Question 11

FceRII

Answer 11

• low affinity
• B cell down regulation
• macrophage phagocytosis
• NK cell
• Dendritic cells
• eosinophils

Question 12

Mast Cell

Answer 12

• located in intestine, skin, airways, nerves, blood vessels

- release pro-inflammatory mediators

Question 13

Connective tissue/skin mast cells

Answer 13

• histamine
• Heparin
• lifespan 6,

Question 14

Intestine/lung mast cells

Answer 14

• chondroitin sulfate
• few histamine
• lifespan <40 days

Question 15

Granules have ___ molecules

Answer 15

proinflammatory

Question 16

Seconds

Answer 16

Granule Exocytosis

• histamine
• serotonin
• tryptase
• kalikreins
• proteases
• proteoglycans

Question 17

Minutes

Answer 17

Eicosanoid Synthesis & Secretion

• Leukotrienes
• Prostaglandins
• Platelet activating factors

Question 18

Hours

Answer 18

Cytokine Synthesis and Secretion
-IL-4,5,6,13
TNF alpha
MIP 1alpha

Question 19

Mast Cells

Answer 19

IL-6
IL-13
(degranulation in presence of IgE)

Question 20

Basophils

Answer 20

IL-3,4,6,13
Histamine
GM-CSF
(basophil differentiation in bone marrow)

Question 21

Eosinophils

Answer 21

IL-8
Degranulation
(terminal effector cells of allergic responses)

Question 22

Th2 cells

Answer 22

IL-5
IL-13
(Eotaxins)

Question 23

Factors of ganules have effects on

Answer 23

GI tract, respiratory tract, blood vessels

Question 24

Enhance mast cell degranulation

Answer 24

stimulation of adrenoreceptors
-Norepinephrine
-Phenylephrine
-block Beta adrenoreceptors
Propranol

Question 25

Inhibition of Mast cell degranulation

Answer 25

blocking of adrenoreceptors - stimulate Beta adrenoreceptors - isoproterenol - epinephrine - salbutamol

Question 26

Immediate inflammation time Vs late phase rxn

Answer 26

10-20 minutes | 6-12 hours

Question 27

Mast cells alpha receptor stimulation: beta receptor stimulation:

Answer 27

- enhances degranulation | - suppresses degranulation

Question 28

Smooth muscles alpha receptor stimulation: beta receptor stimulation:

Answer 28

- contracts | - relaxes

Question 29

Blood vessels alpha receptor stimulation: beta receptor stimulation:

Answer 29

- constricts | - dilates

Question 30

Clinical type I hypersensitivity examples

Answer 30

- allergic anaphylaxis - milk allergy - food allergy - allergies to parasites - atopic dermatitis

Question 31

The most common body system usually affected is the

Answer 31

respiratory system | liver in dogs

Question 32

Allergic anaphylaxis is serious why?

Answer 32

life threatening

Question 33

Dx of Type I hypersensitivity

Answer 33

- intradermal skin testing - passive cutaneus anaphylaxis - measuring IgE

Question 34

Atopic Dermatitis

Answer 34

allergen, IL-31, sensory neurons cause itching

Question 35

Tx of type I hypersensitivity

Answer 35

- avoid exposure - corticosteroids/antihistamines - beta stimulants: epinephrine - alpha antagonists: methoxamine - allergen specific immunotherapy

Question 36

Immunotherapy

Answer 36

- injections, oral drops - increase production of IgG antibodies - main antibody involved is IgE, IgE & IgG will compete for antigen and eliminate antigen faster

Question 37

Atopic Dermatitis tx

Answer 37

block the IL-31 which will stop itching but not the allergen

Question 38

Allergen

Answer 38

antigen that can trigger type I hypersensitivity

Question 39

If the rate of release of vasoactive molecules from these mast cells exceeds its ability to adjust to the rapid changes in the vascular system, an animal will undergo allergic anaphylaxis and may die. T/F

Answer 39

TRUE