hypersensitivity Flashcards
type I hypersensitivity is often referred to as:
allergy, atopy, or immediate hypersensitivity
type I hypersensitivity occurs within minutes after ____ to antigen/allergen
reexposure
initial exposure to antigen and production of IgE antibodies is called ____
sensitization
there is ____ of _____ upon reexposure to allergen
cross-linking; bound IgE
in type I hypersensitivity, release of mediators triggers a ____ response
biphasic
immediate effects of type I hypersensitivity
dilation of BVs, increased vascular permeability, smooth muscle contraction (immediate reaction)
late response to type I hypersensitivity
inflammation (late phase reaction)
____ must bind to mast cells
antigen-specific IgE
immediate response of mast cell degranulation
- vasoactive amines (histamine) and proteases
- synthesis and secretion of lipid mediators (prostaglandins and leukotrienes)
prostaglandins that cause constriction and dilation of BVs
constriction: PGE2
dilation: PGF2a
prostaglandin that acts on thermoregulatory center of the hypothalamus
PGE1
____ is involved in redness, edema, and pain
PGE2
leukotrienes are powerful inducers of:
- bronchoconstriction
- increased vascular permeability
most common asthma signs and symptoms are:
coughing, wheezing, and shortness of breath
asthma treatment strategies include:
- inhaled corticosteroids
- inhaled long-acting beta2 agonists
- leukotriene inhibitors
- cromolyn
These medicines help block the chain reaction that increases inflammation in your airways (example is singulair)
leukotriene inhibitors
Prevents mast cell degranulation through unknown mechanism; Can be administered orally, inhaled, as a nasal spray, or ophthalmic drops
cromolyn
Act on β-adrenergic receptors to cause bronchodilation. “Rescue medications” example is albuteral
inhaled long-acting beta2 agonists
the ___ and ____ of allergens determine the type of IgE-mediated allergic rxn that results
dose; routes of entry
all clinical and pathologic features of immediate hypersensitivity reactions are driven by mediators produced by ____
mast cells
the most severe form of immediate hypersensitivity is ____
anaphylaxis
type II hypersensitivity is called ____
antibody dependent cytotoxicity
therapeutic strategies for autoimmune hemolytic anemia
corticosteroids or blood transfusion
therapeutic strategies for hemolytic disease of the newborn
rhogam injection (anti-Rh antibody)
therapeutic strategies for graves disease
radioactive iodine, anti-thyroid drugs, or thyroid removal
ther. strat for myasthenia gravis
cholinesterase inhibitors and corticosteroids
a grouping of antigens bound to their specific antibodies
immune complex
type III hypersensitivity is ____
immune complex-mediated
type III hypersensitivity can be caused by ____ or ____ antigen
endogenous; exogenous
immune complexes trigger inflammation via three mechanisms:
- mast cell activation
- macrophages release TNF-alpha and IL-1 that induce the inflammatory cascade
- complement activation (C3a, C4a, and C5a)
Caused by an injection of a foreign protein or proteins which leads to an antibody response.
serum sickness
serum sickness is a classic example of a ____, ____ immune complex-mediated syndrome
transient; systemic
a cause of serum sickness; a source of neutralizing antibodies to treat people with poisonous snake bites
antivenom (serum from horses immunized with snake venoms)
a cause of serum sickness; an immunosuppressive agent used for transplant recipients
anti-lymphocyte globulin
a cause of serum sickness; used as a thrombolytic agent to treat heart attack patients
streptokinase (a bacterial enzyme)
in immune complex-mediated hypersensitivity (type III), _____ clump and aggregate in or near blood vessels attracting an acute inflammatory reaction
Ag-Ab complexes
antibody class in type III hypersensitivity is primarily ____ (possibly ___ or ___)
IgG; IgM; IgE
2 examples of type III hypersensitivity
serum sickness and lupus
type IV hypersensitivity is a ____ reaction; mediated by _____ which induce macrophage infiltration in a sensitized individual
cell-mediated; Ag-specific T cells
Small molecules that must become bound to a larger carrier molecule in order to illicit an immune or inflammatory response
haptens
type IV hypersensitivity is often called _____ as the reaction takes 2-3 days to develop
delayed- type hypersensitivity
type IV hypersensitivity is not ____ mediated but ____ mediated
antibody; T cell (mostly Th cells)
___ occurs during first exposure to ag and ____ occurs during reexposure to ag
sensitization; elicitation
3 examples of type IV hypersensitivity
TB test, contact dermatitis, chronic asthma
3 main causes of hypersensitivities
- reaction to self (autoimmunity)
- reaction against microbes
- reactions against environmental antigens
most common disorder of the immune system; affects about 20% of the population
type I hypersensitivity
in type I hypersensitivity, there is rapid ___ and ____ mediated vascular and smooth muscle reaction that is often followed by inflammation
IgE; mast cell
anaphylaxis response is driven by the systemic release of ____ and ____ from mast cells
vasoactive amines; lipid mediators
anaphylaxis causes life-threatening ____ along with severe ____
drop in BP; bronchoconstriction
anaphylaxis is treated with ____ and _____
epinephrine (vasoconstrictor and bronchodilator); antihistamine
type II hypersensitivity characterized by ____ produced by the immune response that bind to antigens on our own cell surfaces
antibodies (primarily IgG and IgM isotypes)
hemolytic disease of the newborn occurs during second pregnancy when ____ mother carries an ____ fetus
Rh- ; Rh+
type III hypersensitivity occurs within ____ after exposure to antigen
hours (3-10)
deposits in type III generally accumulate at sites where ____ is localized or at sites of _____ or _____
antigen; turbulence (vessel branches); high pressure (kidney glomeruli and synovium)
immune complex diseases sometimes manifest as ____, ____, or _____
vasculitis; arthritis; nephritis
cells bearing Fc receptors for ____ and ____ may be crucial for antibody complex mediated hypersensitivity
IgG (or IgM); IgE
symptoms of serum sickness occur within ___ or ____ after injection of serum
days; weeks
serum sickness therapeutic strategies
drug-avoidance, antihistamines, corticosteroids
lupus therapeutic strategies
NSAIDS, corticosteroids, immunosuppressive agents
_____ are important effector cells in the DTH response
macrophages, CD8 T cells, and NK cells
Typically are highly reactive small molecules (hapten) complexed with skin proteins and become internalized by APC’s in the skin
contact dermatitis
contact dermatitis can be elicited by _____
either CD4 or CD8 T cells
