Lecture 10 - Hypersensitivity Flashcards
Order the types of hypersensitivity from fastest to slowest
Type I to Type IV
Type I hypersensitivity
allergic reactions
Type II hypersensitivity
hemolytic anemia
Type III hypersensitivity
serum sickness, lupus
Type IV hypersensitivity
contact dermatitis
What types of cells are present in allergies
mast cells, eosinophils, IgE
what are the two steps to an allergic reaction
step 1 - sensitization (first exposure)
step 2 - subsequent exposure to same allergen
what do allergens in type I sensitivity induce
smooth muscle contraction
edema (vasodilation + increased permeability)
Anaphylaxis
sudden shock syndrome from a massive release of mast cell mediators
what does the severity of anaphylaxis depend on
concentration of allergen
What is Type II hypersensitivity
localized tissue cytotoxicity
B cells are self-reactive or extrinsic antigens bind to RBCs
the antigen-antibody complex employs the
complement system
what is an example of a drug that can induce type II hypersensitivity
penicillin
How does the antigen-antibody complex result in cytotoxicity
phagocytes have complement receptors that facilitate the uptake/degradation of pathogens with C3b, MAC destroys pathogens via pores
hemolytic anemia
blood donor having alloantibodies that bind to recipient RBC
Alloantibodies
produced in response to exposure to incompatible blood group antigens
What is Type III hypersensitivity
The free-floating antibody-antigen complex not associated with the cell affects locally/systemically
what is the result of large immune complexes that are not removed via phagocytosis
tissue damage
what are 3 things that the immune complex formation triggers
- complement activation of neutrophils
- macrophage activation
- complement activation of mast cells
Summarize Arthus reaction
C5a binds to mast cells after formation of immune complex
immune complex binds to mast cells
phagocytes engult complexes
neutrophils release tissue-damaging enzymes
In what locations are complexes likely to be deposited
walls of blood vessels, glomeruli, joints
what complement receptor do immune complexes bind to
CR1
where are CR1 found
circulating phagocytes, RBCs, and platelets
What diseases are associated with deposits in the:
blood vessels
arteritis
What diseases are associated with deposits in the:
glomeruli
glomerulonephritis
What diseases are associated with deposits in the:
synovial fluid
arthritis
List the layers of the glomerulus from outermost to innermost
epithelial cells
subepithelial cells
basement membrane
capillary endothelial cells
mesangial cells
Type 1 MPGN is found where
mesangial and subendothelial cells
Type II MPGN is found where
within basement membrane
Type III MPGN is found where
subepithelial cells
What is serum sickness
formation of antiserum antibody-antibody complexes upon second exposure
What is systemic lupus erythematosus
excessive production of antibodies to self-antigens
Type IV hypersensitivity is also known as
delayed-type hypersensitivity
Type IV hypersensitivity
T cell response to MHC II complexes derived from foreign or modified proteins
Example of Type IV hypersensitivity
poison ivy contact dermatitis
