Innate Immunity Part I (Lec 4)

Question 1

What are the three main functions of the innate immune system?

Answer 1

1) initial host defense response to pathogens that prevents, controls, or eliminates infection
2) eliminates damaged cells and initiates process of tissue repair
3) controls adaptive responses

Question 2

Inflammation is a response by…?

Answer 2

leukocytes and plasma proteins

Question 3

The anti-viral responses lead to…?

Answer 3

inhibition of viral replication

Question 4

What is the difference between distribution of receptors in innate and adaptive immunity?

Answer 4

innate - nonclonal

adaptive - clonal

Question 5

What are the 5 families of microbial PRRs?

Answer 5

TLR, CLR, Nod-like receptors, RIG-like receptors, Cystosolic DNA sensors

Question 6

PRRs on the cell surface bind pathogen-associated molecular patterns from…?

Answer 6

extracellular pathogens

Question 7

What do endosomal TLRs recognize?

Answer 7

nucleic acids of phagocytized microbes

Question 8

Where are TLRs found?

Answer 8

surface and endosomal membranes of DCs, phagocytes, B cells, endothelial cells

Question 9

Where are NLRs found?

Answer 9

cytosol of phagocytes, epithelial cells, and other cells

Question 10

Where are RLRs found?

Answer 10

cytosol of phagocytes and other cells

Question 11

Where are CDSs found?

Answer 11

cytosol of many cell types

Question 12

Where are CLRs found?

Answer 12

plasma membranes of phagocytes

Question 13

True or False?

TLRs may form homodimers or heterodimers.

Answer 13

true

Question 14

True or False?

TLRs recognize both PAMPs and DAMPs

Answer 14

true

Question 15

Where are TLRs 1,2,4,5,6 expressed?

Answer 15

on the cell surface

Question 16

Where are TLRs 3,7,8,9 expressed?

Answer 16

in endosomes

Question 17

TLR3 uses the adaptor protein TRIF and activates…?

Answer 17

the IRF3 and IRF7 transcription factors

Question 18

True or False?

TLR4 can activate both pathways

Answer 18

true

Question 19

TLRs 1,2,5, & 6 use the adaptor protein MyD88 and activate which transcription factors?

Answer 19

NF-kB and AP-1

Question 20

Which TLRs in the endosome use MyD88 and activate both NF-kB and IRF7

Answer 20

TLR 7 and 9

Question 21

What does cytokine IL-12 control?

Answer 21

the adaptive T-cell immune response

Question 22

What does activation of TLRs trigger?

Answer 22

antimicrobial pathways that directly kill the pathogen

note: activation of TLRs can also be detrimental to host: apoptosis, septic shock

Question 23

What activates cells via TLR4?

Answer 23

LPS

Question 24

Microbial lipoproteins activate mammalian immune cells through which TLR?

Answer 24

TLR 2

Question 25

Bacterial DNA sequences containing unmethylated cytosine -guanosine dinucleotides work through which TLR?

Answer 25

TLR 9

Question 26

All TLRs signal through MyD88 with the exception of...?

Answer 26

TLR 3

Question 27

TLR 3 signals through...?

Answer 27

TRIF | note: TRIF is also used in conjunction with TRAM in the TLR4-MyD88-independent pathway

Question 28

True or False? | The secreted form of IL-1beta and IL-18 are produced in inflammasome?

Answer 28

true

Question 29

What is the NLRP?

Answer 29

subfamily of 14 NOD-like receptors that respond to cytosolic PAMPs and DAMPs by binding other proteins and forming signaling complexes called inflammasomes

Question 30

By recruitment to the complex, inflammasomes activate which enzyme?

Answer 30

caspase-1

Question 31

What is the main function of caspase-1?

Answer 31

to cleave the inactive cytoplasmic precursor forms of two homologous cytokines called IL-1beta and IL-18

Question 32

SRs is a group of receptors that mediate what?

Answer 32

the uptake of oxidized lipoproteins into cells

Question 33

SRs SR-A and CD36 are expressed on macrophages and mediate what?

Answer 33

recognition/phagocytosis of microorganisms

Question 34

SRs bind various bacterial constituents based on what?

Answer 34

negative charges

Question 35

Receptors for carbohydrates belong to the C-type lectin family because they bind ___?

Answer 35

carbohydrates

Question 36

The mannose receptor is a C-type lectin which is involved with what?

Answer 36

phagocytosis of microbes

Question 37

True or False? Epithelia at the portals of entry of microbes provide physical barriers, produce antimicrobial substances, and harbor intraepithelial lymphocytes that are believed to kill microbes and infected cells.

Answer 37

True

Question 38

What are antimicrobial peptide defensins?

Answer 38

small cationic peptides that contain both cationic and hydrophobic regions

Question 39

Defensins are produced by epithelial cells of mucosal surfaces and by granule-containing leukocytes including -___ , ____, and ___.

Answer 39

neutrophils, NK cells , and CTLs

Question 40

Synthesis of defenses is stimulated by?

Answer 40

cytokines and microbial products

Question 41

True or False? | Defensin alpha and beta are produced by the same cell types?

Answer 41

false, different cell types

Question 42

True or False? | Defensins have diret toxicity to microbes

Answer 42

true

Question 43

How do defensins kill microbes?

Answer 43

by inserting into and disrupting function of the microbial membrane

Question 44

What do defensins regulate?

Answer 44

regulate activation of cells involved in the inflammatory response to microbes

Question 45

What produces cathelicidins?

Answer 45

neutrophils and barrier epithelial cells

Question 46

Cathelicidins are synthesized as an 18-kD two-domain precursor protein and proteolyticlally cleaved into...?

Answer 46

two protective peptides

Question 47

IL-37 is a cathelicidin that...?

Answer 47

plays an anti-inflammatory role

Question 48

Mast cells are common at sites in the body that are?

Answer 48

exposed to the external environment, such as the skin

Question 49

Mast cells are found in close proximity to blood vessels, where they can..?

Answer 49

regulate vascular permeability and effector cell recruitment

Question 50

Although they do not have direct contact with local cell populations, mast cells can modulate the behavior of these and other neighboring effector cells through....?

Answer 50

the release of mediators

Question 51

Inflammatory DCs may arise from ___ in inflamed tissues.

Answer 51

monocytes

Question 52

Langerhans cells are tissue-resident DCs and may develop from...?

Answer 52

embryonic precursors

Question 53

Innate lymphoid cells (ILCs) developing from a common bone marrow precursor identified by the ___ transcription factor?

Answer 53

Id2

Question 54

Match each subset with the specific cytokines, and list immune function ILC1 ILC2 ILC3

Answer 54

ILC1 -> IL-12 and IL-18, defense against viruses ILC2 -> IL-25 and IL-33, allergic inflammation ILC3 -> IL-1 and IL-23, intestinal barrier function; lymphoid organogenesis

Question 55

What are the functions of NK cells?

Answer 55

recognize ligands on infected cells or cells undergoing other types of stress kill those infected or stressed host cells eliminate reservoirs of infection and thus release intracellular pathogens for phagocytosis

Question 56

NK cells respond to IL-12 produced by macrophages and secrete what?

Answer 56

IFN-gamma, which in turn activates the macrophages to kill phagocytized microbes

Question 57

NK cells will not attack if it recognizes what type of cell?

Answer 57

Class I MHC NK cells have inhibitory receptor that recognizes class 1 MHC expression