6 - Induced Innate Immunity

Question 1

What type of cell are Natural Killer (NK) cells?

Answer 1

innate lymphoid cell

Question 2

What are the 5 genes expressed due to PRR signaling

Answer 2

chemokines (CXCL2) | cytokines | antimicrobial peptides | Type I interferons (IFNa IFNb) | enzymes

Question 3

What are the 2 key enzymes produced due to PRR signaling?

Answer 3

iNOS and COX2

Question 4

What is the role of IFNa (alpha) and IFNb (beta)?

Answer 4

binds to IFNa receptor (IFNAR) &raquo_space;> turns on expression of interferon-stimulated genes (ISGs)

Question 5

What is an example of an IS gene?

Answer 5

PKR (protein kinase R)

Question 6

What are the 3 major pro-inflammatory cytokines?

Answer 6

IL-1b (or IL-1) | TNFa | IL-6

Question 7

What are the 4 functions of the 3 major pro-inflammatory cytokines?

Answer 7

increase vascular permeability | induce fever | recruit/activate other leukocytes | induce hematopoiesis = increase neutrophil/myeloid cell production

Question 8

Why would the pro-inflammatory cytokines want to increase the vascular permeability of the blood vessels?

Answer 8

get more immune cells into circulation &raquo_space;> travel through the vessels &raquo_space;> get to site of infection

Question 9

Which chemokine will be produced due to PRR signaling?

Answer 9

CXCL2

Question 10

What is the purpose of CXCL2?

Answer 10

(IL-8) chemoattractant for neutrophils

Question 11

What is iNOS? What is its purpose?

Answer 11

produces toxic nitric oxide (NO) when activated | causes O2 buildup = targets pathogen to lyse

Question 12

What is COX2? What is its purpose?

Answer 12

converts lipids to prostaglandins | prostaglandins = inflammatory mediator = more inflammation and fever

Question 13

What drug targets COX2?

Answer 13

pain killers like acetaminophen

Question 14

What kind of process is phagocytosis and why?

Answer 14

actin-mediated | needs actin polymerization to occur = pushes membrane forward = moves

Question 15

What is a phagolysosome? What is its function?

Answer 15

when a phagosome fuses with a lysosome | degrades whatever is in phagosome via lysozome enzymes

Question 16

What reactive molecule species will aid in degradation and destruction?

Answer 16

reactive oxygen and nitrogen species (ROS) and (RNS)

Question 17

What are the 4 receptors for phagocytosis?

Answer 17

PRRs | Complement receptors | Opsonins | Fc receptors

Question 18

What are opsonins?

Answer 18

any kind of protein that will bind on the surface of something (like a pathogen) = basically marks it

Question 19

What is the complement receptor for macrophages?

Answer 19

CR3

Question 20

What are the 3 pathways of apoptosis?

Answer 20

apoptosis | neutrophil extracellular traps (NETs) | pyropotosis

Question 21

What are the 3 ways is apoptosis induced?

Answer 21

TNF binds to TNF-receptor | NK cells | cytotoxic T-cells (CTLs)

Question 22

How does Neutrophilic Extracellular Traps (NETs) work and relate to apoptosis?

Answer 22

neutrophils phagocytose pathogen = traps them in &raquo_space;> generate NADPH or ROS to induce apoptosis on pathogen and itself

Question 23

How is pyroptosis induced?

Answer 23

inflammasome activation &raquo_space;> eliminates infected macrophages = releases IL-1b and IL-18

Question 24

Why is inflammation on site of infection good?

Answer 24

recruits leukocytes to site to kill off pathogens

Question 25

What are the 4 signs of inflammation in Greek and what do each of the terms mean?

Answer 25

dolor = pain | calor = hot temperature | rudor = redness due to increase in blood flow | tumor = swelling

Question 26

What induces inflammation?

Answer 26

the 3 key major inflammatory cytokines

Question 27

Are NK cells activated due to PRR signaling? Why or why not?

Answer 27

No because ILCs lack PRRs = not activated by pathogens

Question 28

How are NK cells activated?

Answer 28

by cytokines or whatever is in the environment but NOT by pathogens

Question 29

How do NK cells know which cells to kill? What is significant about the molecule it detects?

Answer 29

kills cells that don't express MHC class I on surface | MHC class I binds to NK inhibitory receptor = prevents NK killing that cell

Question 30

Which cells express MHC class I?

Answer 30

all nucleated cells

Question 31

How would an NK cell know if a cell is virally infected?

Answer 31

viruses target MHC class I expression >>> host cell doesn't express MHC class I >>> NK cell inhibitory receptor can't bind to MHC class I = kills that cell

Question 32

How do NK cells induce apoptosis on target cell?

Answer 32

perforins and granzymes