L26 - 10.2 allergies Flashcards
what is hypersensitivity
immune reactions that is derminetal to the host
- exagratted
how many types of hypersensitivity reactions are there
4
what is the first type of hypersensitivitt reaction
IgE antibodies produced
- immediate reaction
- results in mast cell degranulation and activated eosinophils
what is the 2nd type of hypersensitivity
IgG ABs produced
- binds to self AGs
- Autoimmune response
what is the 3rd type of hypersensitivity
damage done by complex between AG and IgG
- so response is caused by both AG and AB
what is the 4th type of hypersensitivity
immune response by T cells
- leading to delayed hypersensitivity
how long is 4type reaction
more than 4 hours
a day or 2 after AG exposure
-not life threatening
for the reaction to be type 4, what does it need to be even if the irritant is taken away
the body still produces a repsonse to it
other reactions to something
irritant response, food intolerance, side effects
how is type 1 allergy developed
exposure to AG - body sensitizes IgE AB production - re exposure to allergen -allergic response produced
what cytokines are required to switch to IgE
T helper 2
IL4
IL13
how does the mast cell get activated
IgE binds to the allergen
then the complex binds to the receptor on the mast cell
- FceR1 receptors
what does mast cell produce when they get activated
releases substances that cause allergic cymtpoms
mediators from the mast cell
histamine
serotonin
prostaglandins
cytokines
effects of the mast cell mediators
vasodilation, vascular permeability heart rate cardiac contraction bronchoconstriction
