PNP WK3

Question 1

What is the innate immune defense response?

Answer 1

Prevents entry of damaging substances, non-specific

Question 2

What are the different barriers of the innate immune system?

Answer 2

1. Anatomical: skin and mucous membranes
2. Physiological: temperature and pH
3. Cellular: Phagocytes, chemical secreter cells, natural killer cells
4. Inflammatory

Question 3

What are interferons?

Answer 3

antivirals that inhibit virus spread, tell NK cells to absorb the infected cell, can also cause apoptosis of infected cell

Question 3

What is the compliment system?

Answer 3

• cascade of plasma proteins
• activates basophils, mast cells, macrophages/neutrophils = increased inflammation
• promotes opsonization by binding to pathogen

Question 4

What is the mechanism of action for a phagocytic cell (neutrophil, macrophage and dendrites)?

Answer 4

Absorbs infectious agent, phagolysosome destroys infectious agent

Question 5

What is the mechanism of action for chemical secreter cells (basophils and mast cells)?

Answer 5

Releases histamine (vasodilator) and heparin (anticoagulant) to increase inflammation

Question 6

What are eosinphils?

Answer 6

WBC that attach to parasite to destroy through cytotoxic chemicals

Question 7

What is the adaptive immune defense response?

Answer 7

Specific to harmful substances, selective but slow

Question 8

What are the four characteristics of adaptive immunity?

Answer 8

• Antigenic specificity
• Diversity
• Immunologic memory
• Self/non-self recognition

Question 9

What is an antigen?

Answer 9

Molecule that can specifically bind to an antibody, allow body to build defences

Question 10

What are the classes of antigens and their purposes?

Answer 10

IgA: mucous membrane secretions
IgD: bound to B cell surfaces
IgE: bound to mast cells and basophils
IgG: in humoral immunity
igM: early stages of humoral immunity before IgG is produced

Question 11

How do antibodies work?

Answer 11

1. Opsonization: coat pathogen to enhance phagocytosis
2. Complement fixation: coat pathogen and signal blood to destroy it
3. Neutralization: coat pathogen to prevent replication
   *Circulate in body once created to attack same type of antigens in body

Question 12

How does the humoral (B cell) response work?

Answer 12

B cells that recognize antigen are selected for cloning, and are either made into plasma cells to produce antibodies, or memory B cells for long term memory

Question 13

How does the cell-mediated immune response work?

Answer 13

• When a phagocytic cell has a foreign pathogen on its surface (aka an antigen presenting cell), it will go to the lymph node to present to a T cell
• T cell will activate and clone to get rid of infection

Question 14

What is the difference between Tc (cytotoxic T cell) and Th (helper T cell) cells?

Answer 14

Activated Th cells help activate specific B cells to replicate and become plasma cells
Activated Tc cells leave lymph node to find the infected cells and destroy them and induce lysis

Question 15

What is a hypersensitive/allergic reaction?

Answer 15

Reactions that are an excessive reaction to an allergen that can cause tissue damage
- Normal immune response is sensitized
- Excessive immune response is hypersensitized

Question 16

What is IgE mediated/allergic reaction? TYPE I

Answer 16

1st exposure: Antigen presenting cells take allergen to lymph nodes, will produce IgE antibodies
- Th cells will select specific B cell to overproduce IgE
2nd exposure: allergen comes in, binds to mast cell antibodies, causing histamine release
E.G.: Asthma, allergy

Question 17

What is a cytotoxic reaction? TYPE II

Answer 17

• Antigen attaches to cells which are either intrinsic (self-antigen) or extrinsic (foreign but absorbed on surface)
• Picked up by macro. and dend. cells and act as APCs causing B cell response and antigen production against antigen causing cell to die
  E.G. Blood transfusion rejection

Question 18

What is immune complex reaction? TYPE III

Answer 18

• Freely moving antigens bind to antibodies which get lodged in blood vessels, glomeruli etc. and start the inflammatory process
  E.G.: Arthritis, Dermatitis, Vasculitis

Question 19

What is a delayed reaction? TYPE VI

Answer 19

• Antigen enters skin, is engulfed by APCs and taken to lymph and primes Th cells
• Th induces inflammation (releases cytokines) OR activates Tc cells and destroys APCs/ cell with foreign antigen

Question 20

What is the pathophysiology of anaphylaxis?

Answer 20

• Histamine released rapidly from mast cells and basophils (degranulation), an onset of vasodilation and severe hypotension, bronchoconstriction and oedema of mucosa

Question 21

What is the pathophysiology of an autoimmune disease?

Answer 21

• Individuals antibodies against own cells and self tolerance is lost (cannot discern from self and non-self), auto-antibodies trigger inflammation and necrosis

Question 22

What is the treatment for autoimmune diseases?

Answer 22

NSAIDs used for inflammation and pain

Question 23

What is the treatment for anaphylaxis?

Answer 23

• Antihistamines for early stages, epinephrine for anaphylactic reaction

Question 24

What are immunomodulating agents?

Answer 24

Modify body’s immune responsiveness
- Immunostimulants: increase immune responsiveness to fight infection/cancer
- Immunosuppressants: decrease immune responsiveness with hypersensitive/autoimmune reaction

Question 25

What are examples of immunosuppressants?

Answer 25

• NSAIDs
• Corticosteroids: suppress T-cell activity (Prednisone, Dexamethasone, Cyclosporine)
• Calcineurin inhibitors: Prevent T-cell proliferation by blocking cytokines
  Monoclonal antibody therapy: Made by single B-cell clone, make each antibody identical and highly specific

Question 26

What is immunodeficiency (ID)?

Answer 26

Immune system is unable to prevent or fight infection
Primary ID: mainly affects the immune system (B/T cell deficiencies)
Secondary ID: affects immune function due to effects elsewhere in body (stress, drug intake, nutrition, infection, cancer)

Question 27

What is the pathophysiology of HIV/AIDS?

Answer 27

Infects dendritic cells, which are taken to lymph nodes which then destroys Th (CD4+ specifically) cells

Question 28

What is active immunity?

Answer 28

Body is exposed to infectious agent and creates own antibodies, revolves around immunological memory
Natural: infection
Artificial: vaccine

Question 29

What is passive immunity?

Answer 29

Body receives antibodies against substances, no immunological memory
Natural: breast milk
Artificial: immunoglobin preparation

Question 30

What is an difference between a vaccines and an antisera/antiserum?

Answer 30

Vaccine: priming the adaptive immune response to the antigens of a particular pathogen
Antisera: Form of passive immunity for immediate short term protection
- Provides humoral products of immunity,