HYPERSENSITIVITY Flashcards by Iseoluwa Ojo

immune responses can also have deleterious effects on the body

T/F

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immune responses may eradicate the infecting microorganism and at the same time, they can cause- significant tissue damages.

T/F

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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

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Hypersensitivity Reactions

Such a response usually occurs in a sensitized host when it encounters the same antigen for the ______ time.

second

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There are four types of Hypersensitivity Reactions
•
Type I: ________

Type II: _________

Type III: __________

Type IV: _________

Anaphylactic

Cytotoxic

Immune Complex Disorders

Delayed Hypersensitivity

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The first three hypersensitivity reactions are _______ mediated, whereas type IV hypersensitivity involves _______ and ________.

antibody

T cells and macrophages

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Type 1 Hypersensitivity

Aka ___________

Effector cells are ???

Immuno- globulin???

Complement activation?

anaphylactic hypersensitivity

Basophils Mast Cells

IgE

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Type 2 Hypersensitivity

Aka ___________

Immuno- globulin???

Complement activation?

cytotoxic antibody

IgG or IgM

Yes

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Type 3 Hypersensitivity

Aka ___________

Immuno- globulin???

Complement activation?

Immune complex disorders

IgG or IgM

Yes

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Type 4 Hypersensitivity

Aka ___________

Effector cells??

Complement activation?

delayed-type hypersensitivity

T cells, macrophages
No

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Type 1 hypersensitivity

It is also known as immediate hypersensitivity because _________

the reaction occurs within minutes of contact with the antigen or allergen.

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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

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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

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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

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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

immune complex

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Mechanism of Vasoactive Amine Release

The crucial event appears to be ________ of the effector cell surface ____ receptors.

cross-linking

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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

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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

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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

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Type 1 hypersensitivity

Receptor cross-linking also results in the synthesis of mediators from arachidonic acid

T/F

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Allergens are the ______ that are able to elicit __________ responses in certain individuals.

antigens

IgE antibody

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Most naturally occurring allergens have a molecular weight of ______ to ________ daltons.

10,000 to 70,000

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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

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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

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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

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 2. 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

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.