Innate Immunity

Question 1

what are the resident cells that first respond to microbes that have breached the mucosal barrier?

Answer 1

macrophages

mast cells

dendritic cells

Question 2

describe macrophages, mast cells, and dendritic cells

Answer 2

macrophages: engulf and destroy pathogens, clear dead tissue, produce cytokines

mast cells: ellicit immune response by secreting histamine, cytokines, and prostaglandins, and kill bacteria or inactivate microbial toxins using enzymes

dendritic cells: produce many kinds of cytokines that initiate inflammation and stimulate adaptive immunity by displaying antigens to lymphocytes

Question 3

Gram (+) bacteria PAMPs

Answer 3

Nucleic acids: CpG moieties on DNA.

Proteins: pillin, flagellin

Cell wall lipids: lipoteichoic acid

Question 4

Gram (-) bacteria PAMPs

Answer 4

Cell wall lipids: LPS

Bacterial capsule polysaccharides

Proteins: pillin, flagellin

Nucleic acids: CpG moieties on DNA.

Question 5

Virus PAMPs

Answer 5

Nucleic acids: ssRNA, dsRNA, CpG moieties on DNA.

Question 6

Fungi PAMPs

Answer 6

carbohydrate residues: mannam, glucans

Question 7

DAMPs

Answer 7

damage associated molecular proteins

urate crystals, specific alarmins, heat-shock proteins

Question 8

Toll-like receptor (TLR)

Answer 8

receptors on cell surfaces, recognize extrcellular microbial PAMPs

receptors also on endosome membrane and recognize nucleic acids released after microbes are digested

signal transcriptions factors for genes encoding immune response molecules

Question 9

TLR 1

Answer 9

cell surface

bacterial lipopeptides

Question 10

TLR 2

Answer 10

cell surface

bacterial lipopeptides and peptidoglycan

Question 11

TLR 4

Answer 11

cell surface

LPS

Question 12

TLR 5

Answer 12

cell surface

bacterial flagellin

Question 13

TLR 6

Answer 13

cell surface

bacterial lipopeptides

Question 14

TLR 3

Answer 14

endosome cell membrane

dsRNA

Question 15

TLR 7

Answer 15

endosome cell membrane

ssRNA

Question 16

TLR 8

Answer 16

endosome cell membrane

ssRNA

Question 17

TLR 9

Answer 17

endosome cell membrane

CpG DNA

Question 18

NF-kB

Answer 18

nuclear factor kB

transcription factor activated by TLRs

promote expression of chemical mediators of inflammation

Question 19

NOD-like receptors

Answer 19

cytosolic receptors that sense PAMPs and DAMPs and stimulate immune response

Question 20

NOD 1 and NOD 2

Answer 20

contain N-terminal CARD (capsase related domain)

sense bacterial cell wall peptidoglycans

activate NF-kB transcription factor

Question 21

NLRP 3

Answer 21

sense many different microbial and pathologic changes in the cytosol

promotes production of cytokine IL-1B, forms inflammasome with capsase-1

Question 22

RIG-like receptors

Answer 22

recognize RNA produced by viruses in the cytosol and activate signalling pathways that lead to production of type I interferons

Question 23

lectin receptors

Answer 23

recognize carbohydrates - fungal glycans, mannose residues on fungi and bacteria

Question 24

defensins and cathelicidins

Answer 24

peptide antibiotics produced by epithelial cells

Question 25

INF-y

Answer 25

natural killer cell derived interferon-y activates macrophages to kill phagocytosed microbes

Question 26

classical macrophage activation

Answer 26

induced by innate immune signals - TLRs, and by IFN-y involved in destroying microbes and stimulating inflammation

Question 27

alternative macrophage activation

Answer 27

induced by IL-4 and IL-13 involved in tissue repair and stopping inflammation

Question 28

innate lymphoid cells

Answer 28

lypmhocyte-like cells that do not have t cell antigen receptors, but produce cytokines and act like T lymphocytes

Question 29

natural killer cells

Answer 29

sense infected and stressed cells and kill them via their granule proteins, which induce apoptosis in the infected cell also secrete IFN-y, which activates macrophages to kill the associated microbes

Question 30

how are healthy cells protected from detrustion by NK cells?

Answer 30

they have inhibitory receptors (MHC molecules) on their cell surface in addition to the activating receptors

Question 31

which cells are the first-line innate response to viral infection?

Answer 31

natural killer cells: respond 5-7 days after intial exposure

Question 32

how do NK cells get rid of the viral reservoir?

Answer 32

directly by releasing enzymes that induce apoptosis or indirectly by producing IL12 - activating more NK cells, and IFN-y to activate macrophages and inhibit viral replication

Question 33

what happens to recruited immune cells after immune response?

Answer 33

macrophages phagocytoes dead cells or they become pus if large numbers f cells were recruited