Module 2: The Immune System

Question 1

Why are mucosal cells so difficult to colonize

Answer 1

They are regularly replaced and old cells get ejected into the lumen

Question 2

What are functions of dendritic cells

Answer 2

Capture antigens, presents antigen to lymphoid tissue

Question 3

What is the function of lyzozyme

Answer 3

Target peptidoglycan

Question 4

Antimicrobial peptides DON’T bind to…

Answer 4

Neutral charge cells (eukaryotes)

Question 5

Antimicrobial peptides DO bind to…

Answer 5

Negative charge cells (bacterial, gram neg, gram pos)

Question 6

What cells make up the innate immune system

Answer 6

Monocytes/macrophages, neutrophils, NK cells, complement, cytokines, chemokines, dendritic cells, basophils

Question 7

Where do the cells that make up the immune system come from

Answer 7

The bone marrow

Question 8

Common lymphoid progenitor cells turn into…

Answer 8

NK cells and Lymphocytes

Question 9

Lymphocytes

Answer 9

T cells and B cells

Question 10

3 types of T cells

Answer 10

Memory, Cytotoxic and effector

Question 11

2 types of B cells

Answer 11

Memory and plasma

Question 12

Common myeloid progenitor cells turn into…

Answer 12

Dendritic cell, neutrophil, eosinophil, monocyte/macrophage, basophil, mast cells and megakaryocytes/platelets

Question 13

What two cell types of the innate immune system are also important to the adaptive immune system

Answer 13

Macrophages and dendritic cells

Question 14

When is the classical complement pathway activated

Answer 14

Only when you have encounters a pathogen before (needs antibodies)

Question 15

When is the alternative complement pathway activated

Answer 15

When bacterial surface molecules bind C3b

Question 16

What is a protective mechanism used by our cells to prevent opsonization by C3b

Answer 16

H factor (blood protein) binds to sialic acid (coats our cells) which then binds to activated C3b. This complex recruits the I factor and destroys C3b

Question 17

What is the B factor

Answer 17

Binds to bacterial surfaces along with activated C3b and helps in the formation of C5 convertase (start of MAC formation)

Question 18

What is a key difference between chemokines and cytokines

Answer 18

Chemokines attract cells of the IS to the site of infection and make them more active; cytokines activate cells of IS and mediate their response.

Question 19

What mediates the detection of PAMPs

Answer 19

NOD1, NOD2 and other NOD like receptors

Question 20

What is one of the first cytokines present at the site of an infection

Answer 20

IL-1

Question 21

What are two mechanisms of killing by the phagolysosome

Answer 21

Nonoxidative and oxidative

Question 22

What prevents virulence factors from spreading beyond the infection site

Answer 22

Neutrophil extracellular traps

Question 23

Agglutination represents what

Answer 23

A positive reaction in antibody binding

Question 24

What is the first antibody to be produced upon activate of the adaptive immune system to a new antigen

Answer 24

IgM

Question 25

What is cross linking of IgE

Answer 25

When a polyvalent antigen (multiple epitopes recognized by same antibody) binds to two IgE on surface of mast cell/basophil, the receptors will cross link and release histamine and other vasoactive compounds

Question 26

What are 3 types of APCs

Answer 26

Macrophages, dendritic cells and B cells

Question 27

MHC2 is produced only by...

Answer 27

Macrophages, DCs and B cells

Question 28

Extracellular antigens will be presented by...

Answer 28

MHC2

Question 29

Intracellular antigens will be presented by...

Answer 29

MHC1 or MHC2

Question 30

T helper cells...

Answer 30

Produce antibodies, IFN-gamma and activate macrophages

Question 31

Cytotoxic T cells...

Answer 31

Kill any host cell displaying MHC1 that activated them

Question 32

What activates APCs

Answer 32

IL-1

Question 33

What stimulates further productive of APCs after activation

Answer 33

IL-2

Question 34

What are two mechanisms CTLs use to deal with intracellular pathogens

Answer 34

Perforins and granzymes (also used by NK cells) and granulysin to kill intracellular bacteria by pore forming action

Question 35

What are the purpose of NK cells

Answer 35

Act as a backup mechanism to CTLs, if MHC1 expression is low on a cells surface, NK cells will kill it (uses same mechanisms at CTLs just activated in a different way)

Question 36

What induces apoptosis in the innate immune system

Answer 36

NK cells

Question 37

What induces apoptosis in the adaptive immune system

Answer 37

CTLs

Question 38

What is antibody-dependent cell mediated cytotoxicity

Answer 38

Used to deal with intracellular infections, antibodies bind to antigens on infected cells, effector cells bind to those and trigger the release of molecules that induce apoptosis

Question 39

What is a mechanism cells use to deal with pathogens that stop the formation of the phagolysosome

Answer 39

Autophagy, packaging of intracellular stuff for delivery to lysosomes