Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

YR 3 - Illness and Wellbeing > Immunity to Microbial Infections > Flashcards

Immunity to Microbial Infections Flashcards

1
Q

describe innate immunity

A

the first line of defence against pathogen
- general
- non-specific

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

describe adaptive immunity

A

immunity is built up from exposure and vaccinations

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

what cells are present in innate immunity?

A

phagocytes
complement cells
NK cells
lysoszymes

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

what cells are present in adaptive immunity?

A

b lymphocytes and antibodies
t lymphocytes

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

what antimicrobial factors are present within the oral cavity? (5)

A

lysozymes
antibodies - IgA, M and G
antimicrobial peptides
- defensins
- histatins
- LL37

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

what are antimicrobial peptides also known as? what are their charges?

A

host defence peptides
- all short cationic peptides - positive charge

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

where are host defence peptides produced? (3)

A
  • salivary glands
  • epithelial cells
  • leukocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

4 roles of host defence peptides.

A
  • microbial activity
  • antiviral activity
  • immune cell recruitment
  • immune cell activation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

give 3 families belonging to host defence peptides.

A

cathelicidins
defensins
histatins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe defensins. the types, the composure and structure

A

2 types - alpha and beta

  • short peptides
  • 6 paired amino acid cysteine residues
  • pair up to make 3 disulfide bonds
  • structure = beta sheets - protects from overcleavage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how do defensins create disulfide bonds?

A

the r group on amino acid = sulfur

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

alpha defensins
- what are they produced by
- what are they known as?
- where are they stored

A

produced by neutrophils

known as human neutrophil peptides

stored in primary azurophil granules

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

how many HNP-2 are encoded by 3 alpha defensin genes?

A

3 genes
code
4 HNP

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

how can 3 genes encode 4 HNP-2?

A

3 genes
- DEFA 1
- DEFA 3
- DEFA 4

HNP-1 = DEFA1+3
HNP-2 = DEFA-4
HNP3 = combine DEFA1 or 3

HNP-1 and HNP-3 - if the N terminal is cleaved
= the same amino acid sequence as HNP-2

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

how long are HNP’s?

A

29-35 AA

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

what are HNP’s?

A

human neutrophil peptide
- alpha defensins
- host defence peptide

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

which HNPS’s are present in high abundance in the oral cavity?

A

HNP-1
HNP-2
HNP-3

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

do alpha defensins have links to periodontitis?

A

yes, there are increased levels in saliva and GCF when periodontitis are severe
- more neutrophil recruitment during perio

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

do alpha defensins have a link to edentulous patients?

A
  • there are reduced alpha defensins
  • no contact of plaque, not as much recruitment of neutrophils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is neutropenia?

A

decreased levels of neutrophils

21
Q

give an example of a disease caused by neutropenia and its links to alpha defensins.

A

Morbus Kostmann
- children born without neutrophils

  • decreased levels of alpha defensins
22
Q

what 4 bacteria are alpha defensins active against?

evidence was found in vitro

A

streptococcus mutans
p gingivalis
a actinomyocytes
candida albicans

23
Q

alpha defensins regulate the immune system in three ways, explain how

A
  • HNP-1,2,3 = chemotactic for monocytes
  • draw up chemical gradient towards infection
  • increase gingival IL-8 production
  • increase cytokine expression
  • inhibit IL-10
  • increase mast cell degranulation
  • histamine released
  • vasodilation
    = neutrophil recruitment
  • activate dendritic cells
  • promote induction of adaptive immune response
24
Q

two types of defensins

A

alpha and beta

25
how long are beta defensins? where are they usually produced?
36-45 amino acids produced by epithelial cells - gingival cells, salivary glands, tongue and mucosa
26
what colours do alpha and beta defensins stain?
alpha - azure blue beta - brown - indicates hBD-1
27
describe the expression of beta defensins
hBD-1 - always expressed hBD-2 - always only expressed in oral cavity, can be induced in other areas - both expressed between layers: stratum spinosium and stratum granulosum hBD-3 - can be induced - expressed in stratified basal layer hBD-4 - expressed in low levels
28
describe the antimicrobial activity of beta defensions - hBD1,2,3 - level of potency - what bacteria they are active against
hBD1 - least potent - active against: p gingivalis, a actinomycetes, f nucleatum hBD-2 - active against: - gram negative - candida spp hBD-3 - most potent - active against: - gram negative and positive - p gingivalis, a actinomycetes, f nucleatum, s mutans, t denticola
29
how is the immune activity regulated by beta defensins?
hBD2,3 are activated by pro-inflam cytokines - activate DC and T cells - chemotaxis of monocytes, mast cells, T cells, dcs
30
6 steps of how defensins are antiviral
1. target lipid envelope 2. extracellular aggregation 3. receptor blocking/downregulation 4. inhibition of binding 5. block 6. cellular changes
31
describe the first step of defensins antiviral activity.
1. targeting lipid envelope - defensins bind to virus - viral morphology changes - associated with reduced infectivity
32
describe extracellular aggregation - 2/6 antiviral activity
- virus has negative charge - defensins has positive charge - defensins clump as a result - can also polymerise themselves
33
why is aggregation important in anti-viral activity?
- body can recognise aggregated sites - if multiple viruses are aggregated, morphology changes, can only infect one host cell
34
describe receptor blocking/downregulation - 3/6 antiviral activity
- defensin can block interaction between virus and host cell receptors during the infectious stage, don't bind together - host cell can become activated from the binding of defensin - can activate immune response/reduce no of receptors being targeted
35
describe inhibition of fusion - 4/6 antiviral activity
defensins prevent fusion of viral nucleic acids and enzymes being delivered from the enveloped virus onto host cells
36
describe blocking/uncoating - 5/6 antiviral activity
defensins bind to unenveloped virus - bind to the capsid - prevent capsid from releasing viral content
37
describe the cellular changes - 6/6 antiviral activity
- defensin can be detected by host cell - host cell change behaviour - viral replication requires host cell protein - PKC - protein kinase C - stimulated host cells from defensins can reduce the no. of proteins = inefficient replication
38
the 3 families belonging to host defence peptides.
cathelicidins defensins histatins
39
describe the structure of cathelicidins and how they differ from defensins
a-helical structure - no beta sheets - no disulfide bonds
40
what is the only member of the cathelicidin family which is expressed in humans? where is it present and produced by?
LL37 present in saliva, salivary glands and GCF produced by leucocytes and epithelial cells
41
how does LL37 originate? How do you get it to LL37?
as a long peptide chain, in precursor form hCAP-18 - needs to be cleaved by proteases produced by neutrophils: Proteinase 3, Capethsin G and Neutrophil Elastase - occurs outside of the cell - into antimicrobial peptide
42
what is the precursor for LL37 called?
hCAP-18
43
how is LL37 stored?
in its precursor form - hCAP-18 in secondary granules
44
link between LL37 and periodontal disease?
LL37 levels in GCF and saliva increase
45
what bacteria is LL37 active against?
gram negative - p intermedia, p gingivalis, a actinomycetes, f nucleatum gram positive - s gordonii, s sanguines
46
how does Haim-Munk and Papillon-Lefevre Syndrome disease link to LL37?
- patient will have large loss of secondary dentition - patients develop periodontitis due to low levels of LL37 - due to loss of capethesin C gene - lack of cleaved hCAP-18 into LL37
47
how does LL37 regulate the immune response? (4)
1. reduces Candida albicans binding to epithelia - by autoaggregation 2. promotes wound healing - by inhibiting inflam responses - neutralised gram negative 3. stimulates pro inflam responses - stimulate to produce IL8 - enhance cytokines to produce wbc 4. chemoattractant - move neutrophils, T cells, mast cells, monocytes up concentration gradient
48
3 models for how antimicrobial peptides damage bacterial cell membranes?
barrel-stave model toroidal model - most accepted model carpet model
49
describe the toroidal model
- a pore and channel made through bacterial membrane - lined with lipid heads and antimicrobial peptide

YR 3 - Illness and Wellbeing (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions