Phagocytosis

Question 1

What is phagocytosis defined as?

Answer 1

engulfment/ internalization of materials

Question 2

What 3 cells is phagocytosis mostly in? = phagocytes

Answer 2

macrophages/ neutrophils/ DC

Question 3

What are the 5 steps of phagocytosis?

Answer 3

1. Bacterium binds to PRRs on pseudopodia
2. Bacterium ingested- forming phagosome
3. Phagosome fuses with lysosome
4. Bacterium killed/ digested low pH
5. Digestion products released

Question 4

What is the main PRR for phagocytosis?

Answer 4

CLRs

Question 5

Are TLR’s involved in phagocytosis?

Answer 5

no

Question 6

What PRRs are involved in phagocytosis?

Answer 6

CLRs/ scavenger receptors

Question 7

What is an example of a CLR for phagocytosis?

Answer 7

Dectin-1

Question 8

What are 2 examples of Opsonin receptors for phagocytosis?

Answer 8

Complement receptors- CR1/ CR3/ CR4
Immunoglobulin Fc receptors

Question 9

How are microbes recognized?

Answer 9

by receptors on phagocytes

Question 10

How do phagocytes recognize microbes?

Answer 10

soluble opsonin protein bound

Question 11

What is an important part of Opsonin?

Answer 11

mannose-binding lectin serine proteases

Question 12

How does destruction in phagosomes occur after fusion with lysosomes/ granules?

Answer 12

ROS/ RNS/ antimicrobial proteins. enzyme degredation

Question 13

What is a common molecule of ROS/ RNS?

Answer 13

Superoxide anion (O2) + Nitric Oxide (NO)
= Peroxynitrate (ONOO)

Question 14

What form of cell death is induced by TNF binding to TNFR/ NK cells/ T cytotoxic cells?

Answer 14

Apoptosis

Question 15

What is a form of programmed cell death?

Answer 15

Apoptosis

Question 16

What form of cell death activation requires NADPH oxidase/ ROS generation?

Answer 16

Neutrophil extracellular traps NETs

Question 17

What form of cell death involves “filament extension”?

Answer 17

Neutrophil extracellular traps = NETs

Question 18

What form of cell death is induced by inflammasome activation?

Answer 18

Pyroptosis

Question 19

What form of cell death eliminates infected macrophages allowing the release of IL-1B/ IL-18 = proinflammatory cytokines?

Answer 19

Pyroptosis

Question 20

What are 2 early components of inflammation?

Answer 20

increased vascular permeability
recruitment of neutrophils from blood to damage site

Question 21

What are the later stages of inflammation called?

Answer 21

Acute phase responses = APRs

Question 22

What are APRs induced by?

Answer 22

proinflammatory cytokines = IL-1/ TNF-a/ IL-6

Question 23

What does APR include?

Answer 23

opsonin, increased synthesis of antimicrobial proteins by the liver

Question 24

What antimicrobial proteins are synthesized with acute phase responses APR of inflammation?

Answer 24

mannose-binding lectin/ c-reactive protein/ complement proteins

Question 25

Why are NK cells lymphocytes with innate immune functions?

Answer 25

can directly kill pathogens

Question 26

What cells can NK cells target?

Answer 26

pathogen or host as required (have self-receptors)

Question 27

What is unique function of NK cells?

Answer 27

kill cells that have become altered due to stress/ infection

Question 28

What are the 2 things activated NK cells perform?

Answer 28

- kill altered self-cell by releasing perforin/ granzymes/ inducing apoptosis - produce cytokines that induce adaptive responses against altered self-cell

Question 29

How do NK cells select what function? (induce apoptosis or produce cytokines for adaptive response)

Answer 29

induce apoptosis if activating receptors send stronger signals than their inhibitory receptors

Question 30

What NK receptors recognize markers of infection/ stress on cells?

Answer 30

Activating receptors

Question 31

What NK receptors recognize markers of normal cells (MHC ext)?

Answer 31

Inhibitory receptors

Question 32

What are the innate lymphoid cells derived from?

Answer 32

common lymphoid progenitor cells

Question 33

How many common lymphoid progenitor cells are there?

Answer 33

NK cells/ 6 other ILC populations

Question 34

Where are NK cells found?

Answer 34

lymphoid tissue/ recirculate

Question 35

Apart from NK cells where are the other ILCs found?

Answer 35

epithelium

Question 36

Can ILCs be activated directly by pathogens?

Answer 36

no- lack PRRs

Question 37

How many groups of ILCs are there?

Answer 37

3 = ILC1/ ILC2/ ILC3

Question 38

What ILC is related to NK cells/ cytokines/ cell-mediated immunity?

Answer 38

ILC1

Question 39

What ILC is related to cytokines/ parasite immunity/ wound healing?

Answer 39

ILC2

Question 40

What ILC is related to cytokines./ epithelial integrity. lymphoid development/ bacteria/ fungi immunity?

Answer 40

ILC3

Question 41

What innate immune systems are co-opted by adaptive immunity to contribute to antibody-mediated pathogen elimination?

Answer 41

Opsonization/ Complement activation

Question 42

How are dendritic cells an innate/ adaptive bridge?

Answer 42

bring antigens from the infection site/ present to T cells in lymph nodes - activates T cells- differentiate TH/TC

Question 43

What is an example of pathogen avoiding detection by PRRs?

Answer 43

mutation in LPS (not recognized by TLR)

Question 44

What is an example of pathogen blocking PRR signaling pathways- preventing activation/ response?

Answer 44

bacterial proteins with TIR domains that block MyD88/ TRIF

Question 45

What is an example of a pathogen prevent killing?`

Answer 45

rupture phagosome/ escape into cytosol