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Question 1

Explain Type 1 Hypersensitivity

Answer 1

-igE is mediated
first exposure could have little to no response - it will prime the response causing sensitization - stimulate b cells into plasma cells then IgE is produced that binds to mast cells.
subsequent exposure - allergen binds to the IgE on the mast cells which causes degranulation (histamine release) - inflammation, vasodilation and increase in permeability of membranes begin + bronchoconstriction.

Question 2

Explain Type 2 Hypersensitivity

Answer 2

Involves IgG and IgM antibodies and binds to extracellular tissues directly. Produces a lot of inflammation and affecting cell metabolism which leads to negative outcomes.
- binding causes phagocytosis or complement of cells (destruction) and affects cell metabolism which binds to a receptor that inappropriately activate the cell + block and destroy the receptor.

Question 3

Explain Type 3 Hypersensitivity

Answer 3

Involves IgG and IgM antibodies
It does not bind to something, but to something in the blood (floating antigens) - nucleic acids, proteins and peptides.
- deposits in tissues and causes inflammation and tissue damage.
neutrophil recruitment which activate ROS and compounds to kill pathogens which could be direct (bind to cell surface) + within connective tissue.

Question 4

Explain Type 4 Hypersensitivity

Answer 4

Does not involve antibodies

1. delayed response - antigen is ingested by antigen presenting cells - TH cells - inflammation (cytokines) macrophage recruitment = tissue damage.
2. Direct cell mediated cytotoxicity - same as delayed but cytotoxic activation but destroys all cells with the antigen (inflammation + damage occurs) w/ not macrophage recruitment + autoimmune disease and condition.

Question 5

Define Hypersensitivity

Answer 5

An altered immunological response to an antigen that results in a disease or damage to an individual

Question 6

2. You eat a delicious peanut butter cookie. Suddenly you experience a tingling sensation and swelling around your mouth. You start to have some airway constriction. This hypersensitivity is called (a/an):
   a) Allergic reaction
   b) IgE-mediated reaction
   c) Immediate hypersensitivity
   d) Type I hypersensitivity
   e) All of the above

Answer 6

e)

Question 7

3. Describe, with a diagram, the mechanism of a Type I response. Include the sensitizing exposure and the re-exposure (with the immediate and longer-term response).

Answer 7

sensitizing exposure
1. allergen stimulates iGE production which attracts mast cells
Re-exposure to allergen binds to the igE on mast cells and activates them.

Question 8

4. What are 3 actions of histamine?

Answer 8

vasodilation, increase membrane permeability and smooth muscle contraction (broncoconstriction)

Question 9

Where are the antigens located that react with the antibodies in a Type II response vs a Type III response?

Answer 9

Tissues (connective tissue) or blood cells - destroy by inflammation or damage.
Antigens bind to the antibodies (tissues) - non specific - inflammation or tissue damage.

Question 10

6. Describe the following mechanisms (and be familiar with the examples) of a Type II response: a) cell destruction b) inflammation c) altered cell metabolism

Answer 10

a) complement + antibody mediated cell destruction.
- IgG + IgM binds to an antigen on the tissue’s cell surface (opsonization) OR. complement is activated and PHAGocytosis occurs. (ex. blood transfusions)

b) antibodies bind to the extracellular connective tissue - matrix, basement membranes - then it activates the complement to initiate the inflammatory response by - mast cell activation or act as chemokines to attract neutrophils + monocytes.

c) antibodies attach to the receptors, 2 ways.
- blocks or destroys the receptors
- alters the chemicals that usually attach there.

Question 11

Where are the antigens initially located that react with the antibodies in a Type III response? Describe the general mechanism of a Type III response and give an example.

Answer 11

Any tissues - non specific (could be connective)

Question 12

Describe the difference between a systemic immune complex disorder occurring, versus a localized immune complex reaction occurring?

Answer 12

Systemic - affecting the whole body.

Localized - affecting a certain area.

Question 13

Which of the above two mechanisms causes “serum sickness” and what can it be caused by?

Answer 13

Type 3 hypersensitivity - systemic immune complex disorders.

• Ab - Ag complexes are deposited in. a wide range of body tissues.
• ex. venom, antibiotics, foods and drugs.

Question 14

Which of the above two mechanisms causes the “Arthus reaction” and what can it be caused by?

Answer 14

Type 3 - localized immune response.

- usually to be injected drug, producing a local inflammatory response which can be severe.

Question 15

What is not involved, and what is involved, in a Type IV response?

Answer 15

Antigens are not involved and it involves helper T cells (Th1) and cytotoxic cells and inflammatory cells (macrophages)

Question 16

Describe Delayed hypersensitivity

Answer 16

Antigen is ingested by an antigen presenting cell eg. macrophage and transported to the lymph nodes and presented to TH1 cells - then activated to profilterate and migrate to the tissues to release cytokines then chemotaxis of monocytes occur - macrophages release lysosomal enzymes + ROS and comes tissue destruction.

Question 17

Describe cell mediated cyotoxicity

Answer 17

Antigen is ingested and transported to the lymph node + presented to Th1 cells then activated to activate cytotoxic t cells and travels to destroy the cells containing the antigen. (autoimmune disease - diabetes mellitus + viral infections hepititis)

Question 18

Name 3 areas of the body where the effects of mast cell degranulation can be significant.
Describe the effects in each area and relate these to the signs and symptoms that occur in each area.

Answer 18

Gastrointestinal tract - increase peristalsis snd fluid secretion - GI tract expulsion (vomit, diarrhea)

Airways - increase mucus secretion and decrease in diameter - blockage/congestion of airways (wheezing, coughing, phlegm) - swelling and mucus secretion in nasal passage.

Blood vessels - increase in blood flow and permeability - increase tissue fluid - increase lymph flow to lymph nodes, increase in cells + protein in tissues, increase tissue effector response (bp)

Question 19

Allergic Rhinitis: signs + symptoms, treatment and diagnostic test

Answer 19

Signs + symptoms: sneezing, itching and watery eyes
Treatment: antihistamines, decongestants, nasal cortisteroids, allergen avoidance, desensitization therapy.
Diagnostic test: scratch test

Question 20

Describe the mechanism behind desensitization therapy.

Answer 20

Small doses of the antigen over a long period of time. Developing igG so that it neutralizes the allergens, so it does not bind to IgE that causes an allergic reaction.

Question 21

Identify the mechanism behind anaphylaxis and the significance about the types of substances that cause it.

Answer 21

mechanisms: substances that is injected into the blood stream or ingested - affects various tissues.
causes: insect bites/strings, food and antibiotics.

Question 22

What part of this mechanism can cause anaphylactic shock?

Answer 22

inflammatory mediators that cause massive vasodilation and increase in capillary permeability.

Question 23

Anaphylaxis: signs and symptoms and treatment.

Answer 23

itchy rash, flushed skin (red rash), laryngeal edema, wheezing, difficulty breathing, *low bp and tachycardia.

epineprhine

Question 24

What is the difference between an extrinsic and an intrinsic trigger for bronchial asthma?

Answer 24

extrinsic - type 1 - environmental allergens (pollen, animal dander)
intrinsic - not type 1 - respiratory infection, cold air and emotional stress.

Question 25

Describe the signs and symptoms of bronchial asthma.

Answer 25

recurrent episode of wheezing, tight chest, coughing and breathlessness.

Question 26

Define immunotolerance. What occurs if immunotolerance breaks down?

Answer 26

when one does not create a detrimental imnune response to its own cells and tissues (immunological control)

autoimmune disorder

Question 27

Define immunotolerance. What occurs if immunotolerance breaks down?

Answer 27

when one does not create a detrimental imnune response to its own cells and tissues (immunological control)

autoimmune disorder

Question 28

By which two hypersensitivity reactions are autoimmune reactions usually caused?

Answer 28

Type 2 + Type 3

Question 29

Describe two possible mechanisms for an autoimmune disease.

Answer 29

Sequested antigen release - areas not drained by lymph nodes that is full of antigens, with no self antigen release the immune system cab ignore this (fetal development)
Molecular mimicry - where infection w/organism having aG close in structures to a self antigen - not confirmed except for rhueamatic fever/acute glomerulonephritis w/strep.

Question 30

25. Describe systemic lupus erythematosus (SLE) to include the following:
    a. two self-antigens that are molecular (what type of hypersensitivity would this be?)
    b. three self-antigens that are cellular (what type of hypersensitivity would this be?

c. the most characteristic self-antigens
d. be familiar with signs and symptoms (easier to remember if you relate the mechanism of the hypersensitivity to the S&S)
e. treatment

Answer 30

a. type 2 - lymphocytes and platelets.
b. type 3 - nucleic acids, erythrocytes, and coagulative proteins.
c. nucleic acids, erythrocytes, coagulation proteins, lymphocytes and platelets.
d. swelling, painful joints, butterfly rash on face, body rash ^ w/sun exposure and various inflammation.
e. no cure, but NSAID’s can suppress inflammation and pain. Immunosuppressive drugs can be used in more serious instances (internal organ environment)

Question 31

Define “alloimmune response”.

Answer 31

Every cell has various compounds on the surface of cells which is unique per person.
If someone gives blood with CHO chain on the RBC that is the wrong type, they do not have that RBC therefore their body will attack and see it as an antigen.
Thus, create an immune response and destroy it (Type 3)

Question 32

Identify and explain the type of hypersensitivity reaction on which the alloimmune response involved with the ABO blood grouping is based.

Answer 32

Type 3 - IgG and igM is binds to the blood cells which is then damaged by inflammation and destructs its function.

Question 33

Describe the influence of HLA’s/MHCI’s on tissue transplantation.

Answer 33

HCL - produced in chromosome 6 - in relatives it is similar.
Needs tissue typing or else the immune response will react and attack.

Question 34

3 types of tissue rejection

Answer 34

hyper acute: immediate, preexisting recipient Ab to a donor Ag (from previous transplant or transfusion_ - type 3 - Arthus type

acute: within days to months post transplant - biopsy has many lymphocytes and macrophages - type 4 reaction.
chronic: months to years: slow progressive failure of organ transplant (blood vessel damage and fibrosis - weak type 4.

Question 35

Describe graft vs. host disease and in which type of transplant it most often occurs

Answer 35

Transplanted tissue contains the donor’s TH + TC cells that sees the recipients tissues as foreign material then attack it - most common in bone marrow.

Transplant and the recipient is usually immunocompromised, hard to fight back.

Question 36

Describe immunodeficiency and differentiate between primary and secondary.

Answer 36

The failure of the immune system to function normally/properly.

Primary - rare (congential) genetic defect presented at birth

Secondary - common - (acquired) by cancer, aging and infection

Question 37

What is the main clinical manifestation of immunodeficiency?

Answer 37

recurrent severe infections ex. pneunonia, bronchitis, sinusitis, menginiitis, septicemia.

Question 38

What would the type of recurring infection tell you about the type of insufficiency (e.g., viral vs bacterial?)

Answer 38

viral - colds, sore throat - middle ear infection.

bacterial per year - 8+ ear infections, 2 sinitis, 2+ pneumonia or persistent abscessed/fungal infection within a year.

Question 39

Identify the usual cause of a primary immune deficiency (PID), and describe the 5 main classes of PID.

Answer 39

Usually a single gene defect that affects # or function of immune cells.

B lymphocytes - no antibodies circulating - one class sometimes are affected (IgG + IgE)

T lymphocytes - cell mediated immunity = low and Th cells are important for B cells - low antibodies - defect in defence of pathogen or group of pathogen.
Combined (b+t) - most severe (SCID) no Ab, few lymphocytes, thymus reduction.

Complement - severe (c3) - involved in complement protein production pathway (increase infection risk with encapsulated bacteria).
Phagocyte (neutrophils + macrophages) - defects of # and function of macrophages or both + increase bacterial infection rate.

Question 40

Describe the treatments for B cell deficiency, lymphocyte deficiency, and SCID.

Answer 40

Replacing the components.

B cell - gamma globulins are regularly infused (antibody rich plasma)

Lymphocyte - stem cell replacement through implantation w/stem cell rich tissue (bone marrow)

Severe combined - erythrocyte transfusion of adenosine deaminize.

Question 41

Define secondary immune deficiencies and give one example

Answer 41

Acquired deficiency - complications of other pathophysiological conditions.
Eg. Aids. Diabetes mellitus

Question 42

What does “AIDS” stand for? Identify the causative agent of AIDS. How is it transmitted?

Answer 42

acquired auto immunodeficiency syndrome
profound immunosuppression, related to opportunistic infections, malignancies, weight loss (progressive wasting) and CNS degeneration
transmitted through blood, semen, vag fluid, breast milk, IV, sex - not contact or insects.

Question 43

How does the virus actually cause AIDS?

Answer 43

HIV destroys helper T cells that is required for cytotoxic t cells and plasma development that is needed for immunity.

Question 44

What are the early stage symptoms of HIV infection?

Answer 44

flu like symptoms then dissapears.

Question 45

How is AIDS diagnosed? (Be familiar with common opportunistic infections and malignancies, especially one example of an opportunistic infection, and one example of a malignancy.)

Answer 45

Antibodies, antigens and viral RNA. Atypical infections, cancers and chronic disease syndromes - such as thrush. orophangael or esophagael and kaposi sarcoma - skin induced cancer that is viral

Question 46

How is an HIV infection treated? Why is treatment difficult and why is a vaccine unlikely?

Answer 46

Target mechanisms for viral transmission and replication - cannot cure HIV bc it hosts in DNA which antimicrobial agents cannot work well on.

Question 47

What are 3 reasons for the poor antigenic response of the elderly?

Answer 47

• immune system cells cannot profilterate fast
• increase cell numbers the same but decrease cytotoxicity.
• decrease antibody production.

Question 48

Define Allergen

Answer 48

Antigen involved in an allergic response

Question 49

Define Allergy

Answer 49

Hypersensitivity to an environmental antigen

Question 50

Define Pruritus

Answer 50

Symptoms of itching mf

Question 51

Define Urticaria

Answer 51

localized pruritic skin disruption characterized by wheals and hives (reddened bumps + swelling)

Question 52

Define Autoimmune response

Answer 52

Inappropriate response to tissues normally present in the body.

Question 53

Define Alloimmune response #2

Answer 53

in a single species - an immune response to alternate forms of an antigen not found in the recipient’s body (allogen) = eg. ABO Antigen, Rh antigens and tissue transplant.