Type 1 Hypersensitivity Flashcards
Which immune cell mainly mediates type 1 hypersensitivity?
Type 1 is mast cell derived
Which antibody mediates type 2 hypersensitivity?
IgG or IgM
Which antibody mediates type 3 hypersensitivity?
IgG or IgM
What’s the difference between type 2 and type 3 hyper sensitivity?
Type 2 IgG or IgM antibodies produced against cell or tissue antigens and trigger complement. Type 3 IgG or IgM antibodies against soluble antigens in the blood which form immune complexes, triggering complement
Which antibody mediated type 4 hypersensitivity?
T cell mediated
Where are IgG and IgM antibodies deposited in type 3 hypersensitivity?
Vascular basement membrane
What are allergens?
Antigens that initiate immediate hypersensitivity are called allergens
Which cells stimulate IgE?
Activation of Th2 and follicular T-helper cells stimulate IgE
What is the wheel caused from in the wheel and flare response?
Wheel is caused by extravasation of serum and fluid from capillaries-direct effect of histamine
What are the primary binding sites for FceR1 and FceR2 on IgE
C3
Why is IgE conc in serum of normal individuals very low?
Serum IgE has a much shorter half life than other isotypes
Which cytokine is dependant on IgE gene expression?
IL-4
Where are follicular helper T cells primarily located and which cytokine do they mainly produce?
Secondary lymphoid organs, IL-4
Which cytokines do Th2 cells produce and their function?
IL-4, IL-13 (both inducing tissue responses to allergens), IL-5 (promotes eosinophil inflammation)
Where are basophils located?
Not in normal tissue - present in bone marrow
