Immunology: Test 2: 2. Hypersensitivity Type Iii And Iv

Front 1

In type III HS rxns, can complementation be involved?

Back 1

yes! but they don't have to be

Front 2

where in the body are immune complexes formed?

Back 2

liver and spleen

Front 3

Describe Persistent infection

Back 3

- infectious diseases such as malaria, leprosy, viral hepatitis, and others may have long-term persistence of the pathogenic organism leading to chronic production of immune complexes

Front 4

describe autoimmunity

Back 4

- autoimmune diseases where you have chronic production of auto-reactive antibody can lead to prolonged immune complex formation. The normal clearance systems become overloaded and the immune complexes are deposited in the tissues.

Front 5

describe a Inhaled antigen and how immune complexes are involved

Back 5

Immune complexes can form on respiratory surfaces (e.g. alveoli) following repeated exposures to some extrinsic antigens, such as molds, or antigenic material from plants or animals

Front 6

what is an immune complex?

Back 6

The product of an antigen-antibody reaction which may also contain complement system proteins

Front 7

where do immune complexes deposit?

Back 7

blood vessel walls

Front 8

how are immune complexes transported to their site of destruction?

Back 8

Erythrocytes have the receptors for C3b complement protein, and therefore readily bind immune complexes that have fixed complement and transport these complexes to the liver and spleen.

Front 9

What is an Arthus reaction

Back 9

A focal hypersensitivity reaction (usually seen in the skin, or in the lungs) upon repeated exposure to some antigenic material, which induces local immune complex formation, complement activation, leading to acute inflammatory responses (increased blood flow, increased capillary permeability, cell infiltration, histamine and other mediator effects, platelet aggregation), and focal necrotizing vasculitis due to local deposition of immune complexes

Front 10

renal disease could be due to what type of HS rxn?

Back 10

Type III due to deposition of immune complexes in glomeruli

Front 11

Arthus reaction

Back 11

a focal hypersensitivity reaction (skin or lungs) due to repeated exposure to antigen that induces local immune complex formation

Front 12

what is serum sickness

Back 12

a SYSTEMIC vasculitis due to systemic deposition of immune complexes

Front 13

what type of rxn will you see At inoculation site in persons receiving s.c. injections for allergy desensitization

Back 13

Arthus-type reaction (Type III Hypersensitivity)

Front 14

what type of rxn will you see At the site of insect bites

Back 14

Arthus-type reaction (Type III Hypersensitivity)

Front 15

what type of rxn will you see At the site of drug injections

Back 15

Arthus-type reaction (Type III Hypersensitivity)

Front 16

what type of rxn will you see In the early stages of Farmer's lung (= Hypersensitivity pneumonitis)

Back 16

Arthus-type reaction (Type III Hypersensitivity)

Front 17

a bump/wheal is associated with what type of HS rxn? general redness?

Back 17

wheal: Type I (15 minutes)

redness: Type III arthus (takes several hours)

Front 18

what are the symptoms of serum sickness?

Back 18

systemic vasculitis of variable severity, characterized by

fever, lymphadenopathy, arthralgias, and dermatitis.

Front 19

where is Immune complex deposition is most likely to occur?

Back 19

where there is high blood pressure and turbulence. (e.g., renal glomerular capillaries, choroid plexus, and at sites of bifurcation in artery walls)

Front 20

what 2 ways can you measure/detect immune complexes?

Back 20

radioimmunoassay (RIA)

enzyme-linked immunosorbent assay (ELISA) using complement C1q as the bound antigen.

Front 21

what is the timeframe for type IV hypersensitivity?

Back 21

"delayed" in the sense that they usually take more than 12 hours to develop

Front 22

what are teh central mediators of Type IV HS rxns?

Back 22

T cells

Front 23

What is contact hypersensitivity? what type of HS rxn is it?

Back 23

reaction to poison ivy (or nickel) and other haptens, e.g. Allergic Contact Dermatitis, Langerhan’s Cells are important antigen-presenters

Type IV

Front 24

what is Tuberculin type rxn? type of HS rxn?

Back 24

seen in the tuberculosis skin test, principally involves monocytes

Type IV

Front 25

What is a Granulomatous type rxn? type of HS rxn?

Back 25

probably the most important Type IV response clinically; results from the persistence of microbes or other antigens within macrophages

type IV

Front 26

What is the role of Langerhan's cells?

Back 26

they play a role in the sensitization phase of type IV contact reactions

bring the cell to lymph nodes for presentation to T cells

Front 27

what are haptens again?

Back 27

too small own their own to produce a response, need something else (like poison ivy)

bind to some self protein (such as Langerhan cell)

Front 28

what happens in the effector phase of contact type IV rxns? what is primarily responsible?

Back 28

sensitized T cells respond to antigen and produce inflammatory cytokines (INF gamma for example)

help activate macrophages, etc. all acting on the skin to cause separation of the skin (blisters, vasodilation, irritation of nerve endings)

Front 29

what is a granuloma?

Back 29

attempt to close/wall off an infection by the immune system

try to control the spread of infection

Front 30

what forms multinucleated giant cells?

Back 30

the fusion of macrophages or epitheliod cells

Front 31

what are epithelioid cells?

Back 31

large flattened macrophages that have increased endoplasmic reticulum and form a continuous sheet like an epithelium, and may serve to trap material within the granuloma

Front 32

if granulomas can wall of infection, why are they problematic?

Back 32

they can be in a place that obstructs function, such as the lung

Front 33

3 Diseases typically manifesting Type IV granulomatous hypersensitivity

Back 33

Tuberculosis (caused by Mycobacterium tuberculosis bacteria)
- Leprosy (caused by Mycobacterium lepra bacteria)
- Leishmaniasis (a one-celled parasite)

Front 34

Diseases resulting from immune complex formation are divided into three (3) broad groups, what are they?

Back 34

Persistent infection

Autoimmunity

Inhaled antigen

Front 35

Where are immune complexes removed from the body? what do this?

Back 35

Liver and spleen

macrophages are responsible for the removal

Front 36

What is responsible for transporting immune complexes to the spleen/liver? how do they do this?

Back 36

RBCs

they have receptors for C3b complement protein, and therefore readily bind immune complexes that have fixed complement

Front 37

eczema is what type of HS rxn?

Back 37

IV

Front 38

Langerhans cells play a role in what type of HS rxn?

what do they do?

Back 38

Type IV

These antigen-presenting cells activate T cells in a local lymph node and memory cells are produced

Front 39

if you see Epithelioid cells or Multinucleate Giant cells what are you thinking?

Back 39

Epithelioid cells :- large flattened macrophages that have increased endoplasmic reticulum and form a continuous sheet like an epithelium, and may serve to trap material within the granuloma

THINK Granulomatous hypersensitivity

TYPE IV