HYPERSENSITIVITY Flashcards
immune responses can also have deleterious effects on the body
T/F
T
immune responses may eradicate the infecting microorganism and at the same time, they can cause- significant tissue damages.
T/F
T
To distinguish between the beneficial and deleterious effects of the immune responses, the term _________ is used to describe an ______ response that causes ________ in a host
hypersensitivity
exaggerated
tissue damage
Hypersensitivity Reactions
Such a response usually occurs in a sensitized host when it encounters the same antigen for the ______ time.
second
There are four types of Hypersensitivity Reactions
•
Type I: ________
Type II: _________
Type III: __________
Type IV: _________
Anaphylactic
Cytotoxic
Immune Complex Disorders
Delayed Hypersensitivity
The first three hypersensitivity reactions are _______ mediated, whereas type IV hypersensitivity involves _______ and ________.
antibody
T cells and macrophages
Type 1 Hypersensitivity
Aka ___________
Effector cells are ???
Immuno- globulin???
Complement activation?
anaphylactic hypersensitivity
Basophils Mast Cells
IgE
No
Type 2 Hypersensitivity
Aka ___________
Immuno- globulin???
Complement activation?
cytotoxic antibody
IgG or IgM
Yes
Type 3 Hypersensitivity
Aka ___________
Immuno- globulin???
Complement activation?
Immune complex disorders
IgG or IgM
Yes
Type 4 Hypersensitivity
Aka ___________
Effector cells??
Complement activation?
delayed-type hypersensitivity
T cells, macrophages
No
Type 1 hypersensitivity
It is also known as immediate hypersensitivity because _________
the reaction occurs within minutes of contact with the antigen or allergen.
Type 1 hypersensitivity
An individual has circulating ______ or tissue ______-cells that are sensitized by the cytotropic antibody, _____.
Upon subsequent exposure to the allergen, these sensitized cells are triggered to release ________ that produce allergic symptoms.
basophils
mast; IgE
vasoactive amines
Mechanism of Vasoactive Amine Release
The effector cells involved in an allergic response are _______ and ______ .
In general, ______ are found in circulation, whereas ______ are distributed in the tissues.
basophils and mast cells.
basophils; mast cells
Mechanism of Vasoactive Amine Release
The two cell types (basophils and mast cells) are indistinguishable in many of their biologic characteristics:
They express cell surface ____- receptors for ______
They have cytoplasmic granules containing __________
.
They are triggered to release vasoactive amines by similar mechanisms.
Fc; IgE
vasoactive amines
Mechanism of Vasoactive Amine Release
IgE antibodies produced by the plasma cells are bound to the ______ of a ____________ by way of ______ receptors.
Subsequent exposure to the same allergen will cause ________ formation on the cell surface, leading to the release of vasoactive amines.
cell surface
basophil or mast cell
Fc
immune complex
Mechanism of Vasoactive Amine Release
The crucial event appears to be ________ of the effector cell surface ____ receptors.
cross-linking
Fc
Mechanism of Vasoactive Amine Release
At least ____ IgE molecules are occupying the ______ Fc receptors on an effector cell, and the allergen is _____valent, such that it is able to ________________ on the effector cell.
two
adjacent
multi
cross- link the two IgE molecules
Mechanism of Vasoactive Amine Release
One the biologic events resulting from receptor cross-linking is the fusion of _________ and ______, which leads to release of stored, preformed granular contents (the ________ cells become _________).
granular membranes and cell membranes
effector
degranulated
Mechanism of Vasoactive Amine Release
Whereas the released vasoactive amines cause ______ symptoms of an allergic response, the _________ convey the specificity of an allergic re sponse.
general
IgE molecules
Type 1 hypersensitivity
Receptor cross-linking also results in the synthesis of mediators from arachidonic acid
T/F
T
Allergens are the ______ that are able to elicit __________ responses in certain individuals.
antigens
IgE antibody
Most naturally occurring allergens have a molecular weight of ______ to ________ daltons.
10,000 to 70,000
Small antigens may not have sufficient numbers of _______ to facilitate the __________ to trigger a basophil or mast cell degranulation.
while a larger molecule may not be able to ____________________ to reach the sensitized effector cells.
epitopes
Fc receptor cross-linking
diffuse, across the mucosal surface
Various modes of exposure to allergens are identified:
- The ________ is constantly exposed to airborne particles that may cause allergic responses. The most common inhalant allergens are plant pollens, fungal spores, and animal danders.
2.Absorption of allergen from the _______ can also cause allergic responses.
- Direct _______ with pollen or other allergen can cause _______ or even _______ symptoms in a highly sensitive individual.
respiratory airway
digestive tract
skin contact
localized urticaria
systemic
Classification of the Mediators of the allergic response
The mediators of allergic response may be divided into two categories:
_______-formed mediators
_________formed mediators
Pre
Newly
Classification of the Mediators of the allergic response
The mediators of allergic response may be divided into two categories:
Pre-formed mediators; ______ in the ________
Newly formed mediators; _____ after the cells are _________.
stored; granules
synthesized; triggered
Histamine
Histamine causes _____ of the bronchioles and smooth muscle of blood vessels, _____eases capillary permeability, and _____eases mucous gland secretion in the airway.
contraction
incr; incr
Histamine
This ____-formed mediator is stored in the granules and can be released _________ after allergen-antibody reaction.
pre
1 to 2 minutes
Histamine
The duration of histamine activity is approximately __________
10 minutes.
Eosinophil chemotactic factor of anaphylaxis
This is a _____ formed mediator released during _______.
pre; degranulation
Eosinophil chemotactic factor of anaphylaxis
It stimulates ________ to migrate to the site of an antigen-antibody reaction.
eosinophils
Eosinophil chemotactic factor of anaphylaxis
Eosinophils are known to have several functions, which include
(1)___________ of ________complexes
(2) release of the enzymes ______ and ______ . These enzymes ______ the allergic reaction caused by allergens.
phagocytosis
antigen-antibody
histaminase and arylsul fatase
dampen
Arachidonic acid
This is liberated from the ________ by the action of the enzymes ______,_______, and _________
membrane lipid
phospholipase A or phospholipase C and diacylglycerol lipase.
Arachidonic acid
The freed arachidonic acid is then processed by the __________ pathway, or the _______ pathway.
leading to __________ production, the latter leads to __________ production.
cyclooxygenase
lipoxygenase
prostaglandin
leukotriene
Prostaglandin D2 causes vaso_________ and ____eases vascular permeability.
dilation
incr
Prostaglandin D2
The clinical symptoms caused by this compound are similar to those seen with histamine-__________ ——- and ———- reaction.
erythematous
wheal and flare
Prostaglandin D2
However, the prostaglandin D2 effect can persist for as long as __________; the histamine effect lasts approximately __________.
2 hours
10minutes
Leukotrienes C4, D4 or E4 cause ______ and ______ formation.
When inhaled, they cause broncho______.
erythema and wheal
spasm
Leukotrienes C4, D4 or E4
Their bronchoconstrictic potency is ____ to _______ times that of histamine.
30 to 1000
Leukotrienes C4 and D4 have also been shown to stimulate mucous secretion by human airway tissue.
T/F
T
Type II hypersensitivity involves Ig___ or Ig___ antibody against cell surface molecules or tissue components.
G
M
Type II hypersensitivity
The tissue damage-may be mediated by one of the following mechanisms:
(1) accelerated ___________ by the __________ system
(2) blockade of _________ because of ______________
(3)_______-mediated _____ of the target cells, or
(4) The damage of ___________________ by the _________ released by the ______ present at the site of antigen - antibody reactions.
clearance of the antibody–sensitized target cells ; mononuclear phagocyte
normal cellular function ; antibody binding to the target cells,
complement; lysis
innocent by-stander cells or tissue
lysosomal enzymes; neutrophils
Type II Hypersensitivity
_______ Mediated Damage
_______ Mediated Cell Lysis
________________ to tissue components
Antibody
Complement
Cytotoxic antibodies
Type II Hypersensitivity
Antibody Mediated Damage
________ anemia
_________ disease
______________
Hemolytic
Graves’
Myasthenia Gravis
Type II Hypersensitivity
Complement Mediated Cell Lysis
———— reactions
_____________- _______ incompactibility
Transfusion
Hemolytic disease of the newborn
Rhesus
Type II Hypersensitivity
Cytotoxic antibodies to tissue components
eg
________________
Goodpasture’s syndrome
Antibody Mediated Damage : Hemolytic anemia
Hemolytic anemia is frequently associated with (cold or warm?) antibody antibody production against red cell antigen of the _____ system.
The sensitized red blood cells are cleared by the ______ at an accelerated rate, causing aneamia in the afflicted individual..
Warm; Rh
macrophages
Antibody Mediated Damage: Graves Disease
Patients with Graves’ disease have circulating antibodies specific for ___________.
When bound to the __________, these antibodies will stimulate the ________________ to produce _______, independent of the normal feedback control mechanism.
Persistent simulation of the thyroid gland causes _________. These antibodies are known as _______________________
thyroid stimulating hormone (TSH) receptor
TSH receptors
thyroid epithelial cells ; thyroglobulin
hyperthyroidism; long-acting thyroid stimulator (LATS).
Antibody Mediated Damage: Myasthenia Gravis
Here, antibodies against cell surface structure blocks the normal cellular activities.
The antibody against _________ prevents the neurotransmitter, ______, from binding to the receptor at the ______.
_____________ is the clinical manifestation.
acetylcholine receptors
acetylcholine; neuromuscular junction
Muscular paralysis
Complement Mediated Cell Lysis
Transfusion reactions
When the antibody - antigen complex is able to activate the _________, direct cell lysis occurs.
Transfusion of ABO-incompatible blood will result in _____________ because the recipient has antibodies to non-self ABO antigens
complement cascade
lysis of the donor’s red blood cells
____________ are the most important clinical manifestation of this type of hypersensitivity (Type 2)
Transfusion reactions
Complement Mediated Cell Lysis
Hemolytic disease of the newborn (HDNB) is due to ________________________ incompatibility.
The ___________ antigen is the most frequently in volved red cell antigen.
maternal - fetal red cell
Rhesus D (RhD)
Complement Mediated Cell Lysis
Hemolytic disease of the newborn (HDNB)
An RhD-_____ mother be comes immunized to the D antigen on fetal red blood cells because of _________ during delivery
The mother synthesizes Ig____ antibodies against the D antigen.
In a subsequent pregnancy with an RhD- ________ fetus, the Ig____ antibodies cross the placenta and circulate in fetal circulation, causing ______-mediated lysis of the fetal red blood cell.
negative
maternal - fetal blood mixing
G
positive; G
complement
Cytotoxic Antibodies to Tissue Components
Cytotoxic antibodies to tissue components frequently cause _______ responses. The sequence of events includes antibody-antigen reaction, complement activation, generation of such chemotactic factors as _____ and ______, infiltration of the tissue by ________, and release of __________ , which eventually leads to tissue damage.
The classic example is ___________
inflammatory
C3a and C5a; neutrophils
lysosomal enzymes
Goodpasture’s syndrome.
Good Pasture’s Syndrome
The patient develops antibodies against _______________ and ____________
The inflammatory reactions produced by anti- basement membrane antibody deposition account for the clinical symptoms observed in these patients.
The symptoms include _______,______,_______
glomerular and pulmonary basement membranes.
hematuria, renal failure, and hemoptysis
Type III Hypersensitivity
Type III reactions are triggered by the ________________ in tissues, causing __________.
The antibody involved is predominantly ________ or _______
and the antigens can be infecting microorganisms, drugs, or self-antigens.
deposition of circulating immune complexes
inflammation
IgG or IgM,
Type III Hypersensitivity
_________ is usually activated, which greatly _______ the __________
Complement
amplifies
inflammatory response.
Fate of Circulating Immune Complexes
Under normal conditions circulating immune complexes are ________ by the ________________, preventing _________ and associated damage.
rapidly cleared
mononuclear phagocytic system,
tissue deposition
Fate of Circulating Immune Complexes
(Small or Large?) immune complexes are cleared rapidly by the host,
whereas (small or large?) soluble complexes tend to have a prolonged plasma half-life and are associated with tissue deposition, which causes inflammatory responses.
Large
Small
Examples of Type III Hypersensitivity
1) ______ Reaction
2._________ Disorders
3. Destruction of __________
Arthus
Immune Complex
Innocent Bystanders
Examples of Type III Hypersensitivity
- Immune Complex Disorders
a. _____________
b. Vasculitis eg __________
Glomerulonephritis
poly artheritis nodosa
The Arthus reaction is induced experimentally by _________ of the antigen into a ________ animal:
The local antigen-antibody interaction (________________) results in destructive inflammation of _______________, called _________
intradermal injection
sensitized
immune complex formation
small blood vessels
vasculitis.
The Arthus reaction
_________ and ________ appear within __________ and subside within ___________
Local swelling, and erythema
1 to 2 hours
10 to 12 hours.
The Arthus Reaction
Microscopic examination of the tissue reveals _______ infiltration initially; followed by _________ cells and _________ infiltration.
neutrophil
mononuclear; eosinophil
In Arthus reaction,
The ————— and __________degrade the immune complexes.
mononuclear cells and eosinophils
Immune Complex Disorders
The term immune complex disorder is used to describe the diseases associated with clinical features arising from _______________.
The classic example is __________, which frequently develops in patients who receive _________ serum as a form of _____ immunotherapy or immunosup pressive therapy.
For example, _________ to _______
immune complex deposition
serum sickness
heterologous; passive
horse antisera to diphtheria,
Immune Complex Disorders
The patients make _____ against the ________ serum proteins and develop immune complex disorders.
antibodies
heterologous
Immune Complex Disorders
Glomerulonephritis
Deposition of immune complex in the ________ causes inflammatory responses that present with clinical symptoms glomerulonephritis.
Vasculitis
immune complex deposition on _________ causing injury. eg _________ which is a systemic vasculitis characterized by necrotisisng inflammation that affect medium sized and small muscular arteries, limiting function and causing injury.
renal glomeruli
blood vessels
polyarteritis nodosa
Type 3 hypersensitivity
Destruction of Innocent Bystanders
Circulating immune complexes can ______________ to the elements of blood, initiating their destruction and that of innocent bystanders.
nonspecifically adhere
Type 3 hypersensitivity
Destruction of Innocent Bystanders
Drug administration often elicits an antibody response that results in circulating ________ immune complexes.
These completes become ______________, causing __________ hemolysis.
antibody-drug
adsorbed onto the surface of red blood cells
intravascular
Type 3 hypersensitivity
Destruction of Innocent Bystanders
The absorption of immune complexes is thought to be mediated, by the red blood cell surface ______ receptors.
___________ ,________, and __________ are known to cause red blood cell lysis by this mechanism.
C3b
Quinidine, quinine, and phenacetin
Type IV Hypersensitivity
Type IV hypersensitivity, a.k.a ___________ immune re action or ________ hypersensitivity
cell-mediated
delayed
Type IV Hypersensitivity
Type IV hypersensitivity
is mediated by (soluble or insoluble ?) factors or ________ released by _____________
Soluble
lymphokines; sensitized lymphocytes.
Type IV Hypersensitivity
The characteristic histology of the lesion is a __________ cell infiltration.
Such lesions appear _____-______ following antigen challenge and peak within _________
mononuclear
24 to 43 hours
72 hours.
Type IV Hypersensitivity
Antibody and complement are usually directly involved in type IV hypersensitivity.
T/F
F
Antibody and complement are usually not directly involved in type IV hypersensitivity.
Type IV Hypersensitivity: Mechanism of Pathogenesis
The response is initiated by interactions between the antigen and a small number of _____________ that produce
__________ , following their activation.
The lymphokines have biologic activities affecting various cell types, such as _______,_________, and _______
These secondary cells are recruited to the site of reaction.
The overall function of lymphokines is to amplify the response that is initiated by a (small or large?) number of ___ lymphocytes.This is achieved by _________________________________________________________________________
Normal control mechanisms lead to resolution of the reaction; however, multiple antigenic challenges in a hypersensitive individual may lead to the ______ and _______ of the lesion.
Usually the symptoms develop over a period of __________ after antigen exposure, and the histologic examination shows characteristic ___________ infiltration.
sensitized T lymphocytes. ; Lymphokines
macrophages, neutrophils, and other lymphocytes.
Small; T
recruiting and directing the secondary cells, macrophages, neu trophils, and other lymphocytes, both T and B cells
ulceration and- necrosis; 24 to 48 hours
mononuclear
Examples of Type IV
Hypersensitivity Tuberculin-Type Hypersensitivity
Tuberculin-Type hypersensitivity is induced by _________ of the antigen in a __________ individual.
The area of _________ and _______ at the site of injection appears within ___________
subcutaneous injection; sensitized
induration and swelling
24 to 72 hours.
Examples of Type IV
Hypersensitivity Tuberculin-Type Hypersensitivity
Microscopic examination reveals intense ________ cell infiltration around the blood vessels and disruption of the ______________ in the _________
mononuclear
organization of the collagen bundles in the dermis.
Examples of Type IV
Hypersensitivity Tuberculin-Type Hypersensitivity
The classic example is the tuberculin skin test in which _____________ prepared from the culture filtrate of mycobacterium tuberculosis is administered _____________.
purified -protein derivative (PPD)
intradermally
Tuberculin-Type Hypersensitivity
positive response consists of _____ or greater ______ and ________ between ___________ and _______ hours.
10mm
erythema and induration
48 and 72
Tuberculin-Type Hypersensitivity
A positive test indicates that the individual has been ____________
A negative test signifies either ——————- or _____________
exposed to mycobacterium tuberculosis or related organisms
no infection or a false negative due to immunosuppression associated with severe infection.
Examples of Type IV Hypersensitivity : Contact sensitivity
Certain compounds can cause systemic sensitization through ____________.
A second encounter with the same antigen by skin contact results in ____ of the ________ with formation of ________.
direct skin contact
edema; epidermis; microvesicles
Examples of Type IV Hypersensitivity : Contact sensitivity
The microscopic observation of the lesion indicates a _______ cell infiltrate that first appears at 6 to 8 hours and peaks at 12 to 15 hours after exposure to the antigen.
The most common antigens that induce contact sensitivity are _______ and ______
mononuclear
poison ivy and poison oak.
Examples of Type IV
Hypersensitivity Granulomatous hypersensitivity
Granulomatous hypersensitivity results from the - persistent _________________ within _____________ that the cell is ______________________
presence of microorganisms within the macrophages
unable to destroy.
Inert substances, such as talc, may also cause granulomatous hypersensitivity. giant cells.
T/F
T
Granulomatous hypersensitivity
The characteristic cells found in a granulomatous lesion are ___________ ,__________,__________ , which are multinucleated giant cells
lymphocytes
macrophages and epithelioid cells
Epithelioid cells are(well or poorly?) understood.
Poorly
Granulomatous hypersensitivity
The giant cells are _____nucleated with (little or large?) endoplasmic reticulum, ______ mitochondria, and lysosomes.
multi
little
degenerated
Granulomatous hypersensitivity is seen in __________,___________ and __________
tuberculosis, leprosy, and sarcoidosis.
