Hypersensitivity Flashcards
T/F. Hypersensitivity Type I is the most common form.
True.
Rapid ___ and ___ cell mediated vascular and smooth muscle reaction is often followed by inflammation.
IgE; mast
What is the initial exposure to antigen and production of IgE antibodies called?
sensitization
What events occur during sensitization?
- TH2 cells secrete IL’s
2. TH2 cell CD40L binds to B cell CD40
Following sensitization, what is the sequence of events for type I hypersensitivity?
- Sensitization
- Bind of IgE Ab to Fc receptors on mast cells
- Cross-linking of bound IgE upon reexposure to allergen
- release of mast cell mediators
What occurs during the first phase of mast cell degranulation?
immediate effect - dilation of blood vessels, increased vascular permeability, smooth muscle contraction
What occurs during the second phase of mast cell degranulation?
late response - inflammation
What cytokines trigger the production of IgE?
IL-4, IL-5 & IL-13
During the immediate response of mast cell degranulation, vasoactive amines (___ and ___) and proteases are released and synthesis and secretion of lipid mediators (___ and ___).
histamine; serotonin; prostaglandins; leukotrienes
What are prostaglandins and leukotrienes made from?
arachidonic acid
T/F. Prostaglandins relax blood vessels in the lungs.
False, they cause vasoconstriction in the lungs
T/F. Leukotrienes are powerful inducers of bronchoconstriction and increased vascular permeability.
True.
During the late phase reaction of mast cell degranulation, the synthesis and secretion of cytokines, specifically IL-___ causes the infiltration of eosinophils.
5
Bound IgE antibodies activate ___ causing the signal transduction cascade in mast cell degranulation.
ITAMs
Activation of ___ during the immediate phase causes mast cells to release ___ into the environment.
PKC; granules
During the late phase of mast cell activation, ___ kinase causes the breakdown of arachidonic acid into lipid mediators (___ and ___).
MAP; prostaglandins; leukotrienes
What are the most common signs of asthma?
coughing, wheezing, and shortness of breath
Dust mites release the enzyme ___, which cleaves occludin in tight junctions. Once inside the cells, this enzyme is taken up by ___ cells and presented to TH2 cells. Ig___ is produced and binds to mast cells triggering ___.
Derp1; dendritic; E; degranulation
What are two main treatments for asthma?
inhaled corticosteroids; leukotriene modifiers
How does cromolyn block degranulation by mast cells?
by inhibiting leukotrienes and cytokines
What is it called when immediate hypersensitivity causes life-threatening drop in BP accompanied by severe bronchoconstriction?
anaphylaxis
In Type II hypersensitivity, antibodies produced by the immune response bind to antigens on our own cell surfaces. What antibodies are primarily involved?
IgG and IgM
In which disease does the maternal antibody’s target fetal RBC’s for destruction?
hemolytic disease of the newborn (erthroblastosis fetalis)
In what disease do TSH receptor Ab’s stimulate the TSH to over produce thyroid hormone?
Graves Disease
Myasthenia Gravis is caused by ___ receptor Ab’s binding to and blocking the ___ receptor.
ACh
In type III hypersensitivity, Ag-Ab ___ clump and deposit in blood vessels or tissues attracting an acute inflammatory reaction.
complexes
An ___ ___ is a complex consisting of an Ag bound to its specific Ab.
immune complex
T/F. Larger aggregates deposit on vessels and tissues leading to activation and tissue damage.
False, larger aggregates are fixed by complement and cleared from the circulation. Smaller complexes formed in Ag excess deposit on vessels and tissues, ligate to Fc receptors of leukocytes and lead to activation and damage.
In addition to mast cell activation, ___ release TNF-alpha and IL-1 that induce an inflammatory cascade leading to the creation of ___ ___ to recruit other cells.
macrophages; reactive endothelium
What type of cells are crucial for antibody complex mediated hypersensitivity?
cells bearing Fc receptors for IgG (or IgM) and IgE
The Arthus reaction is triggered in the ___ by IgG. Immune ___ form and bind to ___ receptors on mast cells and other leukocytes.
skin; complexes; Fc
Repeated exposure to what types of vaccines lead to Arthus reaction.
tetanus and diphtheria toxoid
What is an example of a transient (resolves itself) systemic immune complex-mediated syndrome?
Serum sickness (type III)
___ ___ is caused by an injection of a foreign protein leading to antibody response. Symptoms occur with in days or weeks and are self-limiting.
Serum sickness
In ___, IgG Ab against ubiquitous ___ Ag in nucleated cells leads to large amounts of small complexes depositing on blood vessels, kidneys, joints, etc… Phagocytosis is activated by ___ receptors and auto reactive T cells become involved leading to damage and death.
SLE; self; Fc
What type of self antigen is targeted in SLE?
genetic material
Type IV hypersensitivity is mediated by Ag specific ___ cells which induce macrophage infiltration in a sensitized individual.
T cells
In Type IV, there is a ___ response to injected or absorbed Ag and symptoms occur within 2-3 days.
delayed
What are type IV hypersensitivity reactions generally initiated by?
haptens
___ are small molecules that must become bound to a larger carrier molecule in order to illicit an immune or inflammatory response.
Haptens
T/F. A TB test is an example of Type IV hypersensitivity.
True.
What are the two phases of contact dermatitis?
sensitization and elicitation
Type IV sensitization occurs after the first exposure to Ag and takes ___-___ days to develop. ___ cells in the skin present the antigen to T cells leading to the formation of CD4 memory T cells specific for the Ag.
10-14; Langerhan
During reexposure to the antigen, the ___ phase of contact hypersensitivity develops within ___-___ hrs. It also involves ___ cell Ag presentation to memory T cells. T cells release ___ and cytokines to recruit other effector cells.
elicitation; 24-48; Langerhan; IFNgamma
T/F. Poison ivy is an example of contact dermatitis.
True.
In chronic asthma, mast cell degranulation leads to ___ (IL-___) and ___ influx. Chronic inflammation can cause irreversible damage and death.
Th2; 5; eosinophil
___ disease or granulomatous inflammation can have an initial presentation in the oral cavity.
Chron’s disease
