Lecture 2

Question 1

What are the two general lines of defense in the immune system?

Answer 1

1. Innate immunity
2. Adaptive immunity

Question 2

What is the first line of defense in the immune system? Is it specific or non-specific?

Answer 2

Innate immunity; non-specific

Question 3

What is the second line of defense in the immune system? Is it specific or non-specific?

Answer 3

Adaptive Immunity; specific

Question 4

What are the two branches of adaptive immunity and what type of cells mediate them?

Answer 4

1. Humoral immunity ; B-cell mediated
2. Cell-mediated; T-cell mediated

Question 5

Which type of immunity is present at birth

Answer 5

Innate immunity

Question 6

Which type of immunity has memory?

Answer 6

Adaptive immunity

Question 7

What is the first level of defense against pathogens?

Answer 7

Anatomic (physical barriers)

Question 8

What are some types of anatomic/physical barriers in the immune system?

Answer 8

skin, oral mucosa, respiratory epithelium, intestine

Question 9

What is the second level of defense in the immune system?

Answer 9

Chemical barrier (complement/antimicrobial proteins)

Question 10

What are three types of antimicrobial peptides?

Answer 10

1. a/b defensins
2. RegIII
3. Histatins
4. Cathelicidin

Question 11

What is Lysozyme and in what bodily systems is it found according to the lecture notes?

Answer 11

• an enzyme that digests the cell wall of bacteria to destroy pathogens
• it is the enzyme in tears and saliva

Question 12

Where specifically does Lysozyme act on bacteria and how does the mechanism work?

Answer 12

Lysozyme creates a defect in the Peptidoglycan layer and exposes the underlying cell membrane to other antimicrobial agents

Question 13

Is Lysozyme more effective against Gram positive or Gram negative bacteria? Why?

Answer 13

• more effective against Gram positive
• Greater accessibility of the peptidoglycan

Question 14

What property of Defensins is important (according to our notes) in its function?

Answer 14

Its amphipathic nature

Question 15

How do defensins work?

Answer 15

• disruption of the cell membranes of microbes
• positively charged defensins interact with charged surface of cell membrane
• defensins insert in the lipid bilayer
• pores form and membrane integrity is lost

Question 16

What is the third level of defense in immunity?

Answer 16

Innate immunity sensor cells

Question 17

What are the two broad categories of innate immune cells?

Answer 17

1. Granulocytes
2. Agranulocytes

Question 18

What are the four types of granulocytes?

Answer 18

1. neutrophils
2. eosinophils
3. basophils
4. mast cells

Question 19

What are the three classes of phagocytes in the immune system?

Answer 19

macrophages, granulocytes and dendritic cells

Question 20

What are the three types of myeloid antigen-presenting cells?

Answer 20

1. monocytes
2. macrophages
3. dendritic cells

Question 21

What are the two types of innate lymphocytes?

Answer 21

1. Natural Killer (NK) cells
2. Innate Lymphocytes

Question 22

What/where are almost all of the cells of the immune system derived from?

Answer 22

Hematopoietic stem cells in the bone marrow

Question 23

What cell lineage comprises most of the cells in the innate immune system?

Answer 23

myeloid lineage

Question 24

What is the predominant granulocyte of all circulating leukocytes? (accounting for >50% of circulating leukocytes)

Answer 24

neutrophils

Question 25

What are granulocytes?

Answer 25

- they contain granules in their cytoplasm - membrane organelles - contain proteins and chemicals important in immune responses

Question 26

What is the second most predominant granulocyte in circulation?

Answer 26

Eosinophils

Question 27

What is the least predominant granulocyte in circulation?

Answer 27

basophils

Question 28

What type of granulocyte is tissue-resident?

Answer 28

mast cells

Question 29

What is the mechanism of action of neutrophils?

Answer 29

phagocytosis and bactericidal mechanisms

Question 30

What is the mechanism of action of eosinophils?

Answer 30

killing of antibody-coated parasites

Question 31

What is the mechanism of action of basophils?

Answer 31

Promotion of allergic responses and augmentation of anti-parasitic immunity

Question 32

What is the mechanism of action of mast cells?

Answer 32

Release of granules containing histamine and active agents

Question 33

What type of cells express MHC-II?

Answer 33

Myeloid antigen-presenting cells

Question 34

What type of cells bridge innate and adaptive immunity?

Answer 34

myeloid antigen-presenting cells

Question 35

What is the most important type of APC?

Answer 35

Dendritic cells

Question 36

What is the mechanism of action of macrophages?

Answer 36

- phagocytosis and activation of bactericidal mechanisms - antigen presentation and cytokine production

Question 37

What is the mechanism of action of dendritic cells?

Answer 37

- antigen uptake in peripheral sites - antigen presentation and cytokine production

Question 38

What do Natural killer cells do?

Answer 38

recognize and destroy virus-infected and tumor cells

Question 39

What do innate lymphoid cells (ILCs) do?

Answer 39

Secrete cytokines to activate innate immune cells

Question 40

What type of cell initiates adaptive immune responses?

Answer 40

Dendritic cells

Question 41

What are the two types of cells of the adaptive immune system?

Answer 41

1. T cells 2. B cells

Question 42

What are the two subtypes of T cells?

Answer 42

1. Helper T cells 2. Cytotoxic T cells

Question 43

What is the subtype of B cells?

Answer 43

Plasma cells

Question 44

What cell lineage comprises the cells of the adaptive immune system?

Answer 44

lymphoid lineage

Question 45

What are the four broad categories of pathogens from smallest to largest?

Answer 45

1. viruses 2. bacteria (intracellular/extracellular) 3. fungi 4. parasites

Question 46

What is/are pathogenic organism(s) that can be present in the extracellular spaces

Answer 46

- viruses - bacteria - protozoa - fungi - worms

Question 47

What are the general mechanisms of protective immunity against extracellular pathogens?

Answer 47

- complement - phagocytosis - antibodies - antimicrobial peptides (epithelial surfaces only) - antbodies (epithelial surfaces only)

Question 48

What is/are pathogenic organism(s) that can be present intracelullarly?`

Answer 48

viruses

Question 49

What are some mechanisms of protective immunity against intracellular pathogens in the cytoplasm?

Answer 49

NK cells Cytotoxic T cells

Question 50

What are some mechanisms of protective immunity against intracellular pathogens in vesicles?

Answer 50

T-cell and NK-cell dependent macrophage activation

Question 51

What do sensor cells express that provide and initial discrimination between self and non-self?

Answer 51

Pattern-recognition receptors (PRRs)

Question 52

How do Pattern-recognition receptors work?

Answer 52

they recognize simple molecules and regular molecular pattern structures known as pathogen-associated molecular patterns (PAMPs)

Question 53

Production of ____ and ____ by sensor cells induces inflammation

Answer 53

cytokines; chemokines

Question 54

How do cytokines act to induce an inflammatory response?

Answer 54

They increase the permeability of blood vessels to allow fluid and proteins to pass into the tissues

Question 55

How do chemokines induce an inflamatory response?

Answer 55

direct the migration of neutrophils to the site of infection

Question 56

Inflammation aids the ____ immune response

Answer 56

innate

Question 57

What are some things that inflammation induces in the body?

Answer 57

vasodilation, redness, warmth, swelling

Question 58

What are the three strategies that the host adopts to deal with the threat posed by pathogens?

Answer 58

1. Avoidance: physical and chemical barrier 2. Resistance: sensor cells and effector mechanisms 3. Tolerance: inflammation