Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immunology > Innate Immunity > Flashcards

Innate Immunity Flashcards

1
Q

2 broad roles of the innate immune system

A
  1. First line of defense that slows the growth of infectious diseases until adaptive immune responses develop
  2. Means of directing adaptive immunity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Innate vs. Adaptive Immunity: Response time

A

Minutes/hours vs. Days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Innate vs. Adaptive Immunity: Specificity

A

Innate immunity is specific for molecules and molecular patterns associated with pathogens and molecules produced by dead/dying cells

Adaptive immunity is highly specific and can discriminate between very minor differences in molecular structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Innate vs. Adaptive Immunity: Diversity

A

Innate immunity has a limited # of conserved germ-line encoded receptors

Adaptive has highly diverse receptors arising from genetic recombination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Innate vs. Adaptive Immunity: Memory responses

A

Innate immunity has some (observed in certain organisms and human NK cells)

Adaptive has persistent memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Innate vs. Adaptive Immunity: Self/nonself discrimination

A

Innate is perfect

Adaptive is good but has some occasional failures that result in autoimmune diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Innate vs. Adaptive Immunity: soluble components of blood

A

Innate: many antimicrobial peptides, proteins, and other mediator like cytokines

Adaptive: antibodies and cytokines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Innate vs. Adaptive Immunity: major cell types

A

Innate: Phagocytes (neutrophils, macrophages, monocytes) NK cells, other leukocytes, epithelial and endothelial cells

Adaptive: T cells, B cells, and antigen presenting cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are 4 barriers that are important in the innate immune defense?

A
  1. Anatomical barriers
  2. Physiologic barriers
  3. Soluble factor-based and chemical barriers
  4. Phagocytic and other cellular barriers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are 3 components of physiologic and chemical barriers?

A
  1. Acid pH
    - of lactic acid and fatty acids in sweat and sebaceous glands prevents microbe growth
    - of the stomach kills most ingested microorganisms
  2. Body temperature (fever response) can inhibit the growth of certain microbes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the structure of antimicrobial peptides?

A

Short cationic peptides (29-35 AA) with an amphipathic structure
- negatively charged portions tend to be buried in the protein while the positive parts are exposed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are defensins and what produces them?

A

One of the most important antimicrobial peptides; made by intestinal paneth cells, epithelial cells, neutrophils, and macrophages

Can kill bacteria very efficiently
-can precent DNA and RNA synthesis by binding to negatively charged structures in the pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are antimicrobial peptides active against?

A

Bacteria, fungi, and enveloped viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the mode of action for antimicrobial peptides?

A

Bind to negatively charged microbial structures and membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the mechanisms of killing of antimicrobial peptides?

A

Disruption of microbial membrane integrity, inhibition of DNA, RNA, and or protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Lysozyme location

A

Mucosal/glandular secretions like tears and saliva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Antimicrobial activities of lysozyme

A

Cleaves the glycosidic bonds of peptidoglycan in bacteria leading to lysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Lactoferrin location

A

Mucosal and glandular secretions

-milk, intestine mucus, nasal + respiratory + urogenital tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Lactoferrin antimicrobial action

A

Binds and sequesters all free iron which limits the growth of bacteria and fungi as well as disrupts microbial membranes and limits the infectivity of some viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Defensins (alpha and beta) location

A

Skin, mucosal epithelia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Defensins antimicrobial activities

A

Disrupt membrane of bacteria, fungi, protozoan parasites, and viruses

Additional intracellular toxic effects

Kill cells and disable viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are 5 examples of ways to penetrate the epithelial barrier and what are example pathogens that make use of this route

A
  • via the airways (Streptococcus pneumoniae)
  • via the gastrointestinal tract (E. coli
  • via the genitourinary tract (Human Immunodeficiency Virus)
  • via cuts in the skin (Staphylococcus aureus)
  • via mosquito bites (West Nile Virus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are 3 elements that are activated after the penetration of epithelial barriers?

A
  1. Soluble innate immune recognition elements
  2. Phagocytic and other cells
  3. Cellular receptors present on innate immune cels that function as sentinel cells in tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are small proteins that cause bacteria to aggregate (enhancing phagocytosis) as well as causing cell wall disruption?

A

Collectins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the 3 major types of interferons?

A
  1. Alpha-interferon produced by leukocytes
  2. Beta-interferon produced primarily by fibroblasts
  3. Gamma-interferon produced by T cells and NK cells
    - not directly induced by viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are interferons?

A

Anti-viral agents

27
Q

What are examples of secretions with antibacterial activity?

A

gastric juice - acid
semen - spermine and zinc
milk – antimicrobial peptides, lactoperoxidase tears, saliva, nasal secretions - lysozyme.

28
Q

The action of complement involves both:

A

the innate and the adaptive immune systems

29
Q

What is complement?

A

a group of ~30 serum proteins that act in an orderly sequence to exert their effect

30
Q

What is the most important component of the complement pathway?

A

C3

31
Q

How does the complement pathway progress?

A

via a cascade of reactions where the product of one reaction is the catalyst for the next

32
Q

What is the end result of the complement pathway?

A

Membrane damaging reaction and enhances clearance of pathogens

33
Q

What 3 things can trigger the complement cascade? Which specific pathways do they trigger?

A
  1. Mannose binding lectin and C-reactive protein (activates lectin pathway - innate immunity)
  2. Microbial cell wall components (alternative pathway - innate immunity)
  3. Antibody-antigen complexes (classical pathway - acquired immunity)
34
Q

What are the 2 anaphylotoxins of the complement pathway?

A

C3a and C5a

35
Q

What complement protein is referred to as opsonin?

A

C3b

36
Q

Where is mannose binding lectin found?

A

Tissue fluid and plasma

37
Q

Binds mannose residues on the glycoproteins and glycolipids of which 3 things:

A
  1. Bacteria
  2. Fungi
  3. Viruses
38
Q

What is CRP and where is it found?

A

called C-reactive protein and it is a protein found in tissue fluid and plasma

39
Q

What does CRP bind to and what does it activate?

A

Binds to phosphatidylcholine and pneumococcal polysaccharide

Activates complement cascade

40
Q

What is the acute phase response and what is it responsible for?

A

The acute phase is the period of disease preceding recovery or death and it is responsible for the production of innate immune effector cells and soluble molecules

41
Q

What are the major signallers of the acute phase response

A

Pro-inflammatory cytokines

IL-1, IL-6, and TNF-α

42
Q

What is the effect of the proinflamatory cytokines of the liver?

A

Tells it to produce more APR proteins

-including complement components

43
Q

What is the effect of the proinflamatory cytokines of the bone marrow?

A

Increase production of white blood cells

44
Q

What is the effect of the proinflamatory cytokines of the hypothalamus?

A

Produce prostaglandins for the fever response and also stimulate the adrenal cortex to produce corticosteroids
-this acts on the liver to increase production of APR proteins

45
Q

Which 2 major cell types are responsible for phagocytosis?

A

Neutrophils and Macrophages

46
Q

What are the 3 mechanisms that phagocytes use to kill microbes?

A
  1. Respiratory burst that generates reactive oxygen and nitrogen intermediates
  2. Non-oxidative methods: hydrolytic enzymes, antimicrobial peptides
  3. Inducible nitric oxide synthase (produces NO)
47
Q

5 steps in the process of phagocytosis

A
  1. Bacteria attached to pseudopodia that form membrane evaginations
  2. Bacteria ingested, forms phagosome
  3. Phagosome fuses with lysosome
  4. Bacteria killed, digested by lysosomal enzymes
  5. Digested products released from cell
48
Q

What 2 features of PAMPS make then a good target for recognition

A
  1. Highly conserved and very difficult for microbes to change
  2. Absent from host cells
49
Q

What is recognized by the TLR and NOD receptors?

A

Structural motifs (PAMPs) in microbes

50
Q

TLRs that recognize nucleic acids are located where?

A

Inside the cell (endosome/lysosome)

51
Q

repeats of which amino acid form the ligand binding exterior domain of TLRs?

A

Leucine rich repeats

52
Q

What 3 things can the TLR signal following activation ?

A
  1. MAP kinase pathway
  2. Interferon regulatory factor 3/7
  3. NF-κB
53
Q

What are the 5 inflammation promoting genes that are regulated by NF-κB?

A
  1. Inflammatory cytokines
  2. Chemokines
  3. Adhesion molecules on endothelial cells
  4. Immune effector molecules
  5. Costimulatory molecules
    - critical for the initiation of adaptive immunity
54
Q

TLRs are direct inducers of the maturation of which cell type?

A

Dendritic cells

55
Q

What do the TLRs induce the DC to produce/express

A

CD80/CD86/CD40

Upregulation of MHC II

Production of IL-12

56
Q

What 2 cytokines can induce dendritic cells to mature indirectly?

A

TNF and IL-1

57
Q

What are the 4 innate immunity effector cells

A

Neutrophils, Macrophages, Dendritic cells and NK cells

58
Q

What are the 2 type 1 interferons?

A

IFN-α and IFN-β

59
Q

What activates IFN-α and IFN-β production?

A

Presence of viral RNA or DNA in the cell

-via TLR stimulation

60
Q

What do x then induce (antiviral mechanism)

A

Antiviral responses in neighbouring cells by binding to the IFN-α/β receptors

This leads to mRNA degradation within the cell and the inhibition of protein synthesis

The cell is then refractory to viral growth

61
Q

What cells can the IFN-α/ß activate? What effect does this have on the cell

A

NK cells which increases their lytic activity of virally infected cells

62
Q

How does the NK cell use a dual receptor mechanism to discriminate between healthy and infected cells?

A

Virally infected cells will down regulate class I MHC

NK cells have a dual receptor mechanism and if there is no class I MHC to interact with the inhibitory receptor, the cell will be killed

63
Q

What type of cell produces 100-1000x more type I interferon when it comes into contact with viruses

A

Plasmacytoid dendritic cells

64
Q

What do plasmacytoid cells recognize?

A

viral ssRNA using a TLR

Immunology (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions