Hypersensitivity

Question 1

What produces the type I hypersensitivity reaction?

Answer 1

Allergen

Question 2

In Type I hypersensitivity _________ antibody is over produced

Answer 2

IgE

Question 3

Overproduction of IL4 in type I hypersensitivity leads to increased ________ and ______cell activation

Answer 3

Th2 and Bcell

Question 4

The FceR receptors binds _________

Answer 4

Fc region of antibody

Question 5

Binding of antigen to IgE on mast cells initiates?

Answer 5

Degranulation of mast cells ->release of vasoactive molecules, chemotactic molecules, cytokines, and enzymes.

Question 6

Degranulation of mast cells induces?

Answer 6

Acute inflammation and systemic effects

Question 7

What is the role of IL4 in induction of IgE response?

Answer 7

IL4 is produced by Th2 cells and promotes development of Th2 and activation of Bcells to produce IgE

Question 8

Dendritic cells express a __________ receptor Thant can bind IgE. The processed antigen stimulates _________ cell response which is the production of __________ to further promote IgE response

Answer 8

FceRII; TH2; Cytokines

Question 9

Where are mast cells located?

Answer 9

Intestine, skin ,airways, and around nerves

Close to blood vessels

Question 10

What do mast cells release?

Answer 10

Pro-inflammatory mediators

CT and skin
Histamine
Heparin

Intestine and lung
Chondroitin sulfate
Histamine

Question 11

What are the biological properties of IL33

Answer 11

Major mediator of inflammatory reaction
Stimulating release of cytokines from cells

Mast cells- degranulation in presence of IgE
Basophils - differentiation in bone marrow
Eosinophils- terminal effector cells of allergic response
Th2 - eoxtaxins (chemokines attracting more eosinophils)

Question 12

Mast cell degranulation is enhanced by the stimulation of _________________________ and blocking of _____________

Answer 12

A-adrenoreceptors

• > norepi
• > phenylephrine

B-adenoreceptors
-> propranolol

Question 13

Mast cell degranulation of inhibited by stimulation of _________________ and blocking of _________________

Answer 13

B-adenoreceptors

• > isoproterenol
• > epi
• > salbutamol

a- adenorecptors

Question 14

What is the usual chemical mediator of type I hypersensitivity

Answer 14

Histamine

Question 15

What are 3 methods of diagnosis of type I hypersensitivity

Answer 15

Intradermal skin testing (inject antigen)

Passive cutaneous anaphylaxis

Measure IgE

Question 16

What are 5 ways to treat type I hypersensitivity ?

Answer 16

Avoid contact 
Corticosteroid 
Antihistamine 
B stimulants /a antagonist 
Immunotherapy

Question 17

What is type II hypersensitivy

Answer 17

Reaction against non-self RBC antigens

Question 18

If an animal blood donor doesn’t match recipient what immune response occurs?

Answer 18

Production of IgM antibodies

• agglutination
• opsonization
• phagocytosis
• hemolysis

Question 19

What is hemolytic disease of the newborn (HDN)?

Answer 19

Newborn has a different blood type than the mother

During birth the mother is exposed to baby’s blood type and produces antibodies against it

Newborn ingests colostrum with antibody that act against its own RBC

Question 20

What is a type III hypersensitivity ?

Answer 20

Antibody + antigen + complement => immune complex

IC deposited in tissues -> chemotatic peptide recruits neutrophils
Leads to inflammation and tissue destruction

Question 21

What are the two types of type III hypersensitivity ?

Answer 21

Local and general

Question 22

What is a local type III hypersensitivity reaction?

Answer 22

Immune complexes are formed within the tissue

Question 23

What is the pathogenesis of an anthus reaction

Answer 23

Immune complex

• > macrophage ->NO, IL-1, and TNFa
• > neutrophils
• > C5a
• > mast cells
  - -> neutrophil accumulation -> tissue destruction

Question 24

What is a generalized type III hypersensitivity ?

Answer 24

Immune complexes form in the blood

• > removed by erythrocytes/ macrophages
• > production of high amount of IC

Question 25

Where are immune complexes of a generalized type III hypersensitivity commonly deposited ?

Answer 25

Glomeruli > glomerulonephritis Synovial -> arthritis Choroid plexus

Question 26

What are the three types of glomerulonephritis ?

Answer 26

Type I- mesangial and subendothelial region (Ig and C3) Type II- deposit in glomerular basement membrane (contains C3) Type III -subepithelial region (Ig and C3)

Question 27

What is a type Iv hypersensitivity ?

Answer 27

Tcell mediated inflammation against an antigen Eg. Tuberculin

Question 28

How does a type IV hypersensitivity induce inflammation

Answer 28

Antigen -> Dendritic cells -> migrate to lymph node -> antigen presented to Tcell -> Tcell produce cytokines -> macrophages and basophils activated to release serotonin, enzymes, oxygen, and metabolites ->inflammation

Question 29

What are the 4 tuberculin tests in cattle?

Answer 29

Single intradermal Comparative Short therma Stormot

Question 30

What two tuberculin tests can be used in postpartum cattle and in infected/advanced stage cases?

Answer 30

Short thermal - time consuming Storming - 3 visits ,

Question 31

What tuberculin test is used for routine testing and what is its disadvantage?

Answer 31

Single intradermal Prone to false positives Poor sensitivity

Question 32

What is allergic contact dermatitis ?

Answer 32

Reactive chemicals on skin -> bind skin proteins -> complexes processed by Langerhans cells in dermis

Question 33

How can atopic dermatitis be differentiated from allergic contact dermatitis

Answer 33

Atopic - type I hypersensitivity -> intradermal testing (immediate result) -> high eosinophils levels Allergic contact- type IV hypersensitivity -> patch test (delayed response) -> high macrophage levels

Question 34

How is cell proliferation measured to determine a type IV hypersensitivity reaction

Answer 34

Thymidine uptake Cells stimulated to divide by an antigen/mitogen-> Thymidine incorporated into dividing cells -> uptake measured by radioactivity

Question 35

How is cell death used to measure a type IV hypersensitivity reaction

Answer 35

Target cells take up chromium51 -> cytotoxic cells kill -> chromiym51 is released -> radioactivity measure

Question 36

How can ELISA be used to measure a type IV hypersensitivity reaction

Answer 36

IFN-y is released from lymphocyte in response to antigen -> assay for amount of IFN produced ELISplot : antibody against IFN into well -> add lymphoid cells -> add antigen -> lymphoid cells produce cytokine that binds to antibody in well -> assay