Which Hypersensivities are mediated by Ab's?
Which Hypersensitivities are mediated by T-Cells?
Response Time for Hypersensitivities I-IV
- I: 2-30 mins
- II: 5-8 Hr
- III: 2-8 Hrs
- IV: 24-72 Hrs
What type induces a Cytolytic Response?
Which type induces the formation of Immune Complexes?
Which type is the DTH?
Allergies and Atopy are caused by which type?
Immediate, Type I, Hypersensitivity Rxn
Genetic predisposition to develop clinical Type I allergies
Type I is mediated by
- (which is attached to Mast cell)
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
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 =>
- Smooth M contraction
- 10-20 mins
- Smooth Muscle Contraction
- +/-Mucous Production
- +/- Puritis
- Wheel and Flare
- 6-12 hrs
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
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)
Clinical Signs resulting from Anaphylaxis
- Edema in shock organ
- Smooth M Constriction/Bronchial Constriction
Primary Shock Organ in Horses (2):
Primary Shock Organ in Ruminants:
Primary Shock Organ in Dogs:
Symptoms Associated w/ anaphylactic shock in a dog:
- Muscle weakness
- Depressed RR
- Blood pooling in GI and in Liver
Primary Shock organ in Cats:
Drugs/Haptenes become antigenic when...
they bind to host proteins
Skin rash consisting of red, edema, plaque-like eruptions, which are often pruritic
Urticaria is most often observed in ___ & ___
dogs and horses
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)
- Anti-IgE Ab
Hyposensitization works by...
switching the Ab response away from IgE to IgG