Hypersensitivity

Question 1

T/F. Hypersensitivity Type I is the most common form.

Answer 1

True.

Question 2

Rapid ___ and ___ cell mediated vascular and smooth muscle reaction is often followed by inflammation.

Answer 2

IgE; mast

Question 3

What is the initial exposure to antigen and production of IgE antibodies called?

Answer 3

sensitization

Question 4

What events occur during sensitization?

Answer 4

1. TH2 cells secrete IL’s

2. TH2 cell CD40L binds to B cell CD40

Question 5

Following sensitization, what is the sequence of events for type I hypersensitivity?

Answer 5

1. Sensitization
2. Bind of IgE Ab to Fc receptors on mast cells
3. Cross-linking of bound IgE upon reexposure to allergen
4. release of mast cell mediators

Question 6

What occurs during the first phase of mast cell degranulation?

Answer 6

immediate effect - dilation of blood vessels, increased vascular permeability, smooth muscle contraction

Question 7

What occurs during the second phase of mast cell degranulation?

Answer 7

late response - inflammation

Question 8

What cytokines trigger the production of IgE?

Answer 8

IL-4, IL-5 & IL-13

Question 9

During the immediate response of mast cell degranulation, vasoactive amines (___ and ___) and proteases are released and synthesis and secretion of lipid mediators (___ and ___).

Answer 9

histamine; serotonin; prostaglandins; leukotrienes

Question 10

What are prostaglandins and leukotrienes made from?

Answer 10

arachidonic acid

Question 11

T/F. Prostaglandins relax blood vessels in the lungs.

Answer 11

False, they cause vasoconstriction in the lungs

Question 12

T/F. Leukotrienes are powerful inducers of bronchoconstriction and increased vascular permeability.

Answer 12

True.

Question 13

During the late phase reaction of mast cell degranulation, the synthesis and secretion of cytokines, specifically IL-___ causes the infiltration of eosinophils.

Answer 13

5

Question 14

Bound IgE antibodies activate ___ causing the signal transduction cascade in mast cell degranulation.

Answer 14

ITAMs

Question 15

Activation of ___ during the immediate phase causes mast cells to release ___ into the environment.

Answer 15

PKC; granules

Question 16

During the late phase of mast cell activation, ___ kinase causes the breakdown of arachidonic acid into lipid mediators (___ and ___).

Answer 16

MAP; prostaglandins; leukotrienes

Question 17

What are the most common signs of asthma?

Answer 17

coughing, wheezing, and shortness of breath

Question 18

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 ___.

Answer 18

Derp1; dendritic; E; degranulation

Question 19

What are two main treatments for asthma?

Answer 19

inhaled corticosteroids; leukotriene modifiers

Question 20

How does cromolyn block degranulation by mast cells?

Answer 20

by inhibiting leukotrienes and cytokines

Question 21

What is it called when immediate hypersensitivity causes life-threatening drop in BP accompanied by severe bronchoconstriction?

Answer 21

anaphylaxis

Question 22

In Type II hypersensitivity, antibodies produced by the immune response bind to antigens on our own cell surfaces. What antibodies are primarily involved?

Answer 22

IgG and IgM

Question 23

In which disease does the maternal antibody’s target fetal RBC’s for destruction?

Answer 23

hemolytic disease of the newborn (erthroblastosis fetalis)

Question 24

In what disease do TSH receptor Ab’s stimulate the TSH to over produce thyroid hormone?

Answer 24

Graves Disease

Question 25

Myasthenia Gravis is caused by ___ receptor Ab’s binding to and blocking the ___ receptor.

Answer 25

ACh

Question 26

In type III hypersensitivity, Ag-Ab ___ clump and deposit in blood vessels or tissues attracting an acute inflammatory reaction.

Answer 26

complexes

Question 27

An ___ ___ is a complex consisting of an Ag bound to its specific Ab.

Answer 27

immune complex

Question 28

T/F. Larger aggregates deposit on vessels and tissues leading to activation and tissue damage.

Answer 28

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.

Question 29

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.

Answer 29

macrophages; reactive endothelium

Question 30

What type of cells are crucial for antibody complex mediated hypersensitivity?

Answer 30

cells bearing Fc receptors for IgG (or IgM) and IgE

Question 31

The Arthus reaction is triggered in the ___ by IgG. Immune ___ form and bind to ___ receptors on mast cells and other leukocytes.

Answer 31

skin; complexes; Fc

Question 32

Repeated exposure to what types of vaccines lead to Arthus reaction.

Answer 32

tetanus and diphtheria toxoid

Question 33

What is an example of a transient (resolves itself) systemic immune complex-mediated syndrome?

Answer 33

Serum sickness (type III)

Question 34

___ ___ is caused by an injection of a foreign protein leading to antibody response. Symptoms occur with in days or weeks and are self-limiting.

Answer 34

Serum sickness

Question 35

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.

Answer 35

SLE; self; Fc

Question 36

What type of self antigen is targeted in SLE?

Answer 36

genetic material

Question 37

Type IV hypersensitivity is mediated by Ag specific ___ cells which induce macrophage infiltration in a sensitized individual.

Answer 37

T cells

Question 38

In Type IV, there is a ___ response to injected or absorbed Ag and symptoms occur within 2-3 days.

Answer 38

delayed

Question 39

What are type IV hypersensitivity reactions generally initiated by?

Answer 39

haptens

Question 40

___ are small molecules that must become bound to a larger carrier molecule in order to illicit an immune or inflammatory response.

Answer 40

Haptens

Question 41

T/F. A TB test is an example of Type IV hypersensitivity.

Answer 41

True.

Question 42

What are the two phases of contact dermatitis?

Answer 42

sensitization and elicitation

Question 43

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.

Answer 43

10-14; Langerhan

Question 44

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.

Answer 44

elicitation; 24-48; Langerhan; IFNgamma

Question 45

T/F. Poison ivy is an example of contact dermatitis.

Answer 45

True.

Question 46

In chronic asthma, mast cell degranulation leads to ___ (IL-___) and ___ influx. Chronic inflammation can cause irreversible damage and death.

Answer 46

Th2; 5; eosinophil

Question 47

___ disease or granulomatous inflammation can have an initial presentation in the oral cavity.

Answer 47

Chron’s disease