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Which Hypersensivities are mediated by Ab's?
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Which Hypersensitivities are mediated by T-Cells?
IV
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Response Time for Hypersensitivities I-IV
- I: 2-30 mins
- II: 5-8 Hr
- III: 2-8 Hrs
- IV: 24-72 Hrs
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What type induces a Cytolytic Response?
Type II
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Which type induces the formation of Immune Complexes?
Type III
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Which type is the DTH?
Type IV
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Allergies and Atopy are caused by which type?
Type I
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Allergy-
Immediate, Type I, Hypersensitivity Rxn
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Atopy-
Genetic predisposition to develop clinical Type I allergies
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Type I is mediated by
- IgE
- (which is attached to Mast cell)
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Normal response to environmental Ag's, involves the production of:
IgG or IgA
-
In a Type I response, IgE can bind to (3):
- Mast Cell
- Basophil
- Eopsinophil
-
What triggers a mast cells to degranulate in a type I?
Cross-limking of 2 Ab's once an Ag is bound
-
Degranulation of Mast Cells in a Type I =>
-
Histamine ->
- Smooth M contraction
- Vasodilation
-
Early Phase...
Time:
Symptoms (5):
- Time:
- 10-20 mins
- Symptoms:
- Vasodilation
- Smooth Muscle Contraction
- +/-Mucous Production
- +/- Puritis
- Wheel and Flare
-
Late Phase...
Time:
Symptoms:
- Time:
- 6-12 hrs
- Symptoms:
- Redness
- Edema
- Pruritis
-
Early Phase is mediated by:
Histamine & Heparine from Mast Cells
-
Late Phase is mediated by:
Chemotactic Factors from Mast Cells that attract Eos and Neut's
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What=> Asthma
Late Phase of Type I
-
Severity of a Type I depends on...
- Degree of sensitization
- Amount of Ag involved
- Route of admin
- (= number and location of mast cells, eosinophils and basophils)
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Clinical Signs resulting from Anaphylaxis
- Vasodilaton/Hypotension
- Edema in shock organ
- Hypovolemia
- Smooth M Constriction/Bronchial Constriction
-
Primary Shock Organ in Horses (2):
-
Primary Shock Organ in Ruminants:
Pulmonary
-
Primary Shock Organ in Dogs:
Liver
-
Symptoms Associated w/ anaphylactic shock in a dog:
- Excitement
- Vomiting
- Defecation/Urination
- Muscle weakness
- Depressed RR
- Blood pooling in GI and in Liver
-
Primary Shock organ in Cats:
Lungs
-
Drugs/Haptenes become antigenic when...
they bind to host proteins
-
Urticaria-
Skin rash consisting of red, edema, plaque-like eruptions, which are often pruritic
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Urticaria is most often observed in ___ & ___
dogs and horses
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What causes urticaria?
Inhaled or ingested antigens, drugs or insect bites
-
Dx tests for Type-I (3):
- Serum IgE
- Measure IgE, specific to suspested allergen (intradermal tests)
-
Tx for Type I:
- Epinephrine (Norepi or dex SP in cattle)
- Antihistamines
- Corticosteroids
- Anti-IgE Ab
- Hyposensitization
-
Hyposensitization works by...
switching the Ab response away from IgE to IgG
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