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