Hypersensitivity Flashcards
What produces the type I hypersensitivity reaction?
Allergen
In Type I hypersensitivity _________ antibody is over produced
IgE
Overproduction of IL4 in type I hypersensitivity leads to increased ________ and ______cell activation
Th2 and Bcell
The FceR receptors binds _________
Fc region of antibody
Binding of antigen to IgE on mast cells initiates?
Degranulation of mast cells ->release of vasoactive molecules, chemotactic molecules, cytokines, and enzymes.
Degranulation of mast cells induces?
Acute inflammation and systemic effects
What is the role of IL4 in induction of IgE response?
IL4 is produced by Th2 cells and promotes development of Th2 and activation of Bcells to produce IgE
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
FceRII; TH2; Cytokines
Where are mast cells located?
Intestine, skin ,airways, and around nerves
Close to blood vessels
What do mast cells release?
Pro-inflammatory mediators
CT and skin
Histamine
Heparin
Intestine and lung
Chondroitin sulfate
Histamine
What are the biological properties of IL33
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)
Mast cell degranulation is enhanced by the stimulation of _________________________ and blocking of _____________
A-adrenoreceptors
- > norepi
- > phenylephrine
B-adenoreceptors
-> propranolol
Mast cell degranulation of inhibited by stimulation of _________________ and blocking of _________________
B-adenoreceptors
- > isoproterenol
- > epi
- > salbutamol
a- adenorecptors
What is the usual chemical mediator of type I hypersensitivity
Histamine
What are 3 methods of diagnosis of type I hypersensitivity
Intradermal skin testing (inject antigen)
Passive cutaneous anaphylaxis
Measure IgE
What are 5 ways to treat type I hypersensitivity ?
Avoid contact Corticosteroid Antihistamine B stimulants /a antagonist Immunotherapy
What is type II hypersensitivy
Reaction against non-self RBC antigens
If an animal blood donor doesn’t match recipient what immune response occurs?
Production of IgM antibodies
- agglutination
- opsonization
- phagocytosis
- hemolysis
What is hemolytic disease of the newborn (HDN)?
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
What is a type III hypersensitivity ?
Antibody + antigen + complement => immune complex
IC deposited in tissues -> chemotatic peptide recruits neutrophils
Leads to inflammation and tissue destruction
What are the two types of type III hypersensitivity ?
Local and general
What is a local type III hypersensitivity reaction?
Immune complexes are formed within the tissue
What is the pathogenesis of an anthus reaction
Immune complex
- > macrophage ->NO, IL-1, and TNFa
- > neutrophils
- > C5a
- > mast cells
- -> neutrophil accumulation -> tissue destruction
What is a generalized type III hypersensitivity ?
Immune complexes form in the blood
- > removed by erythrocytes/ macrophages
- > production of high amount of IC
Where are immune complexes of a generalized type III hypersensitivity commonly deposited ?
Glomeruli > glomerulonephritis
Synovial -> arthritis
Choroid plexus
What are the three types of glomerulonephritis ?
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)
What is a type Iv hypersensitivity ?
Tcell mediated inflammation against an antigen
Eg. Tuberculin
How does a type IV hypersensitivity induce inflammation
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
What are the 4 tuberculin tests in cattle?
Single intradermal
Comparative
Short therma
Stormot
What two tuberculin tests can be used in postpartum cattle and in infected/advanced stage cases?
Short thermal - time consuming
Storming - 3 visits
,
What tuberculin test is used for routine testing and what is its disadvantage?
Single intradermal
Prone to false positives
Poor sensitivity
What is allergic contact dermatitis ?
Reactive chemicals on skin -> bind skin proteins -> complexes processed by Langerhans cells in dermis
How can atopic dermatitis be differentiated from allergic contact dermatitis
Atopic - type I hypersensitivity -> intradermal testing (immediate result) -> high eosinophils levels
Allergic contact- type IV hypersensitivity -> patch test (delayed response) -> high macrophage levels
How is cell proliferation measured to determine a type IV hypersensitivity reaction
Thymidine uptake
Cells stimulated to divide by an antigen/mitogen-> Thymidine incorporated into dividing cells -> uptake measured by radioactivity
How is cell death used to measure a type IV hypersensitivity reaction
Target cells take up chromium51 -> cytotoxic cells kill -> chromiym51 is released -> radioactivity measure
How can ELISA be used to measure a type IV hypersensitivity reaction
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
