Immunology: Hypersensitivity
Antigens responsible for allergic type reactions are called____________
allergens
When CD8 cells activate against self or foreign antigen, what is the result?
direct lysis of host cell
In myesthenia gravis, what occurs when acetylcholine receptors are recognized as "non-self" and targeted?
down-regulation of receptors causing weakness and paralysis
In chronic asthma, there are large numbers of ________________ in the bronchial smooth muscle.
eosinophils
True or false: It is possible for antibodies to bind to hormone receptors:
True This is associated with Type II hypersensitivity reactions.
Anaphylaxis, hay fever, and food allergies are considered which type of hypersensitivity?
Type I
IgE is associated with which type of hypersensitivity?
Type I
Which type of hypersensitivity is involved with mast cell-derived mediators and cytokine-mediated inflammation (eosinophils, neutrophils)
Type I
Which type of hypersensitivity is involved with complement, opsonization and phagocytosis, and abdnormalities in cellular function (ex: signaling)
Type II
Characterized by antibodies (IgG and IgM) that attach cellular or extracellular matrix targets. There is subsequent recognition and lysis by the immune system:
Type II (antibody-mediated)
SLE is associated with which type of hypersensitivity?
Type III
Serum sickness is associated with which type of hypersensitivity?
Type III
Which type of hypersensitivity is involved with complement, and receptor mediated recruitment and activation of leukocytes (only).
Type III
"Delayed Hypersensitivity"
Type IV
Poison ivy reaction is an example of which type of reaction?
Type IV
RA is a type of which hypersensitivity reaction?
Type IV
The skin TB test is an example of which type of hypersensitivity reaction?
Type IV
Which type of hypersensitivity is involved with macrophage activation, cytokine-mediated inflammation, and direct target cell lysis?
Type IV
What period of time is required after initial antigen exposure for an individual to be sensitized (in type IV)?
24 hours
In what tissues would mast cells be found?
All connective tissues
Type II hypersensitivity
Antibody-mediated diseases
Type IV reactions are mediated by which lymphocytes?
CD4 and CD8
IgE production starts with activation of which type of T cell?
CD4 type 2
What is the function of IgE in hypersensitivity reactions?
Causes release of vasoactive mediators by mast cells upon re-exposure to allergen.
Biochemical signals produced from the high affinity E receptor elicit what 3 responses from the mast cell?
Degranulation, synthesis and release of lipid mediators, synthesis and secretion of cytokines
True or False: Hypersensitivity reactions are unlikely to have a genetic link.
False: Hypersensitivity reactions have a strong genetic component.
Myesthenia Gravis is a Type _____ hypersensitivity, where the ____________________ _________________ is recognized as non-self.
II, acetylcholine
Graves Disease is an example of a Type ____ hypersensitivity where antibodies simulate ______________ funciton in the absence of TSH.
II, thyroid
What cytokine is released by TH2 cells to generate production of IgE antibodies?
IL-4
Type III hypersensitivity reactions are usually associated with which antibody?
IgG
Type III hypersensitivity
Immune complex-mediated diseases
Do mast cells release mediators on initial exposure?
No, they release mediators after repeat exposure to allergen.
Type IV hypersensitivity
T cell-mediated diseases
In late phase reaction of Type I hypersensitivity, what cytokines are produced by activated mast cells and what is the outcome?
TNF, IL4 and IL5 (produced by TH2) eosinophil and neutrophil inflammation, eosinophil activation and protease secretion
What causes tissue damage with TYpe III hypersensitivity reactions?
The antigen-antibody complex is deposited in the tissues, there is inflammatory response at the site of deposition.
Type III hypersensitivity responses are driven by what?
The site of disposition indicates where and to what extent the response occurs.
What is accomplished by coating of IgE antibodies on mast cells?
They are more sensitive and responsive to repeated exposure to the allergen that initiated the response.
Most severe type 1 reaction:
anaphylaxis
In Type III hypersensitivity, the hypersensitivity process is initiated by ____________ ____________
antibody binding
List the three factors during which the antigen-antibody complex would CAUSE disease:
excessive amounts produced, not efficiently cleared, become deposited in tissues.
Where does IgE bind?
high affinity Fc receptors and heavy chain on mast cells.
List the mediators produced by activated mast cells:
histamine, proteases, arachidonic acid metabolites (prostaglandins and leukotrienes)
Type I hypersensitivity
immediate hypersensitivity
In RA, specifically where in the body is an antigen "percieved"?
joint synovium
In asthma, what mediators are secreted by mast cells in the bronchi?
leukorienes
List the type of lipid mediator that causes smooth muscle relaxation:
leukotrienes
Hypersensitivity diseases are classified based on what?
mechanism of tissue injury
When antigen-antibody complexes deposit in the joints, renal glomeruli, and microvasculature, what are the two types of local inflammatory responses?
neutrophil and eosinophil activation, compliment activation
List the type of lipid mediator that causes vascular dilation:
prostaglandins
What causes tissue damage in Type II hypersensitivity reactions?
release of ROI and lysosomal enzymes
Treatment for which problem results in serum sickness?
snake bite
Eosinophil activation and protease secretion can cause what detrimental effect to the host?
tissue damage
In this type of hypersensitivity, recognition of self fails, antibodies attach to self-targets causing activation of macrophage and neutrophils. There is subsequent inflammation and release of ROI and lysosomal enzymes (causing tissue damage
type II
What do vasoactive amines do to the vascular and smooth muscle?
vascular dilation and smooth muscle contraction
