Please enable JavaScript.
Coggle requires JavaScript to display documents.
FUN 12: Overactivation of immune response - Hypersensitivity +…
FUN 12: Overactivation of immune response - Hypersensitivity + Autoimmunity (i)
Allergy
response to harmless antigen
type 1 hypersensitivity
hyperinflamm
reaction determined by where antigen contacts immune system
Th2 - IgE mediated (imbalance)
reexposure - stronger reactions
allergens = small highly soluble proteins
Can cause reactions @ low concs @ mucosal sites
hygiene hypothesis
Atopy = allergic predisposition
Fc epsilon R
= IgE R on mast cells + basophils
only 2 IgE's required - highly sensitive
Allergic mediators
immediate = granule contents
histamine
TNF alpha
proteases
heparin
cause sneezing, congestion, itching, wheezing, runny nose
over mins = lipid mediators
PGs
LTs
cause wheezing
over hrs = cytokines
IL 4 + 13
cause eosinophil recruitment
eosinophils act on goblet cells to make mucus
Stages of allergic response
1) Sensitisation
1st allergen encounter
B cells process antigen + T cells activate
IgE produced
mast cell degranulation
2) Effector phase
acute
within mins of reexposure
allergen recognised by IgE coated mast cells
3) Late response
ck's released
Asthma
mild/moderate
Th2
IL 4 + 13
severe
Th1,2,17
TSLP
cytokine that causes T cells entering lungs to tend towards Th2
FCRs
recognise Fc portion of antigen-antibody complex
gamma on macrophages, dendritic cells, NKs
epsilon on mast cells, basophils, eosinophils
Penicillin Allergy
Penicillin binds to RBCs
RBCs now non-self
antibodies + macrophages kill RBCs
Complement - MAC
intravasc haemolysis