Zusammenfassung der Ressource
Hypersensitivity Reactions
- Type 1) Immediate
- Stage 1: Sensitization. Under normal
curcumstances- IgM would be produced
with APC production but release of IL4 (and
some genetic predispositions) will promote
an isotypic switch to IgE antibodies
- Stage 2: The activation stage: There is X
reaction between the allergen and IgE which
are located on MAST cells- degradation
- Stage 3: Effector stage: Degranualtion
releases pharmocologically activ particles:
chemokines, vasoactive and chemoactive
molecules as well as enzymes which
promote inflammation
- Atopc dermatits, milk
allergy in Jersey cows,
Mites and Penicillins
- Type 2
- This is when there are Ig's binding
to normal cells and causing
destruction via ADCC and
complement cascades.
- IgG bind to ACH receptors of the
oesophagus causing MegaE
(Myasthenia Gravis
- IgG bind to platelets
causing
thrombocytopenia
- Maiden mares who are exposed (and
develop Ig) to their foal (father
inherited) antbodies during pregnancy.
These Ig's are then passed into
colustrum and cause neonatal jaundice
- Type 4) Delayed
- **These DO NOT INVOLVE ANTIBODIES**- No B cells
- This is when an antigen in inoculated into the skin
and a SLOW (2-3d) inflammtory reponse is actvated
- 1) The antigen migrates to local LN and APC'S are
activated as the pathogen is processed and
presented
- 2) The T cells and NK cells travel to the inoculation
site and induce inflammation
- Allergic contact dermatitis occurs
when certain chemicals/ toxins
are absorbed into the skin
- M. TB testing in cattle- a
positive tuberculin test occurs
if the animal has had prior
exposure
- Type 3
- This is an immune COMPLEX mediated
reaction where a large number of [Ig-Ab]
activate the complement system
- In normal circumstances these complexes are
either phagocytosed or taken up by liver
kuppfer cells for destruction. In these cases the
antigen is chronic via... 1) Persistent infection, 2)
An auto-immune issue or 3) An inhaled antigen
- Rheumatoid arthritis
- The ARTHUS response to
vaccinations- this is a local
issue which is common in
cats
- Serum sickness: This is a sytemic
response to passive immunization
which may induce vascuitism edema
and swelling of joints/ LN's
- These have been characterised into 4 types- all
activated by an ALLERGEN, those that become systemic
are anaphylactic.. Pollen, fish, penicillin, Brazil nuts etc
- Benefits include the release of chitinases which
degrade insects, fungi etc