Immunity system Vs Pathogens L16 Flashcards
1
Q
what is a microbiome
A
microbial communities of tissues (skin, oral mucosa, gastrointestinal tract)
2
Q
effect of microbiome
A
cause no damage to host, can perform important functions
3
Q
are different microbiomes recognised
A
Immune system must be able to recognise difference
4
Q
what cells are humans mainly made of
A
more prokaryotic than eukaryotic cells
5
Q
when do commensals become pathogens
A
when in the wrong location
6
Q
what is the difference between pathogens and commensals
A
whether they cause damage
7
Q
what is the distribution of PRRs
A
have more effect on pathogens and less effect on commensals
8
Q
what are the cell surface receptors
A
toll-like receptors
9
Q
what are the pathogenic factors
A
virulence factors so they can attach/invade (NLR’s)
10
Q
what are indigenous microbiota like
A
non-invasive
11
Q
what do commensals interact with
A
only apical surface TLRs
12
Q
what does the microbiome do
A
evolved to lessen inflammation
13
Q
what is on the apical surface
A
Microbiome on apical surface of villi – microvilli
14
Q
what happens when invasion occurs in mucosa
A
invading come into contact with cytosolic NLR’s
15
Q
what are the TLRs like on the apical surface compared to basolateral
A
TLR’s on apical surface are less responsive than ones on host basolateral side of epithelial cells
16
Q
where do commensals interact with
A
less responsive apical side
17
Q
how is inflammation lessened
A
by dampening epithelial cell TLR signalling
18
Q
what is the mucosal immune system
A
area of an intestinal villus
mucosal immunity functions independently of regional lymph nodes to control inflammation induced by microbiota or to stimulate
19
Q
what are IECs
A
intestinal epithelial cells
20
Q
what respiration do bacteria have
A
anaerobic and aerobic
21
Q
what shape are bacteria
A
cocci and bacilli
22
Q
what gram are bacteria
A
gram-positive
gram-negative
23
Q
what is a capsule
A
protects against phagocytosis
24
Q
what do bacteria contain
A
toxins
25
what are flagella for
attachment
motility
injection needle
26
how are flagella used as injection needle
allows bacterial factors to come into the host cell through end of the flagella
27
what is bacteria attachment for
help attach bacteria to the surface
28
how does phagocytosis work against bacteria
Host immune cell recognises the bacteria, engulfs it and breaks it down in phagolysosome
29
how does bacteria counter phagocytosis
covers self in capsule so isn’t recognised
30
what do antibodies do to help against bacteria
immune system has an antibody that recognises the capsule so can be taken up by macrophage/neutrophil
prevent toxins entering cell
31
what does the complement assist
phagocytosis and enhances inflammation
32
what do helper T cells activate
activate macrophage to kill intracellular bacteria in MHC recognition
33
what do cytotoxic T cells kill
kill infected host cells and activated macrophages
34
how does bacteria escape phagosome
using hemolysins
35
how does phagosome-lysosome fusion become inhibited
secreting proteins into host cytosol, which interfere with the signalling pathways that cause the fusion
36
what does bacterial evasion induce
Induce production of anti-inflammatory cytokines
37
what is inhibited by bacterial evasion
Inhibit signal transduction of proinflammatory cytokines
38
what is expressed in bacterial evasion
Express proteins that can cause apoptosis of T cells
39
what happens after pathogen escapes phagosome
the host cells can form an autophagosome
40
what is the immune system like
highly regulated mechanism
41
what is delivered in immune system
intracellular pathogen to lysosomes
42
what is one of the most common causes of gastroenteritis in the world
Campylobacter jejuni
43
what is Campylobacter jejuni characterised by
abdominal pain, fever and diarrhoea
44
what is the flagella of Campylobacter jejuni important for
colonisation
45
what happens if Campylobacter jejuni
| invasion
Invasion of host cells activates production of cytokines
46
what is sialylation
addition of sialic acid groups onto oligosaccharides
47
what is LOS
Lipooligosaccharides
48
what can flagella be used as in Campylobacter jejuni
can be used to as an apparatus to secrete proteins such as Campylobacter invasion antigen (cia)
49
what is GBS
Guillain-Barré Syndrome
50
what does LOS do
mimic structure of human gangliosides (molecular mimicry)
51
what can antibodies against the C. jejuni LOS lead to
autoimmune response, resulting in Guillain-Barré Syndrome
52
is GBS fatal
can be fatal
53
what are the symptoms of GBS
vary from mild muscle weakness to potential paralysis
54
what is CDI
Clostridium difficile infection
55
what does clostridium difficile toxins cause
cause severe inflammatory reaction leading to microulcerations
56
what are the two main toxins of Clostridium difficile
TcdA and TcdB
57
what are the toxins like that clostridium difficile secrete
Large secreted proteins
58
what do clostridium difficile toxins interact with
epithelium cause inflammatory response
59
what is SLP
surface layer proteins
60
what does TcdA cause
apoptosis in monocytes
61
what is SLP like
highly variable across different strains, may have role on evasion of host immune response
62
where are defensins secreted
by specialist cells in intestinal epithelia, can reduce tissue damage due to toxins
63
what do defensins do
reduce inflammatory cytokine production, thereby regulating the immune response
64
what is staph aureus
Common human pathogen; component of the commensal flora and major cause of invasive infection
65
what us staph aureus responsible for
majority of skin and soft tissue infections in humans
66
what can staph aurea cause
invasive and life-threatening infections
67
what is the problem with the treatment of staph aureus
complicated by the emergence of methicillin-resistant S. aureus (MRSA) strains, which are becoming increasingly resistant to multiple antibiotics
68
what does staph aureus interfere with
innate immune response
69
what does staph aureus express
wide variety of virulence factors
| Expresses SpA protein
70
what does SpA protein that staph aureus expresses cause
binds to antibodies and prevents opsonophagocytic killing
71
what is needed to clear staph aureus
neutrophils
72
what are NETs
neutrophil extracellular traps
73
what are NETs made of
comprised of DNA and antimicrobial peptides
74
what do antibodies do to viruses
Antibody blocks ability of virus to invade cells
75
how do antibodies prevent virus entry into cell
Antibody recognizes the PAMPs and virus cant get into the cell
76
what happens to cell surface if infected
MHC class 1, if infected can express peptides on surface of that pathogen
77
what happens if MHC class 1 on cell surface
Cytotoxic lymphocytes can recognise and kill the pathogen
78
if no expression of MHC class 1 what happens
natural killer cells compensate, recognise no MHC class 1 on surface so has to kill cell
79
what do viruses do to prevent MHC class 1 on surface
avoid NK cells recognition viruses can display a decoy MHC I-like molecule on cell surface (human cytomegalovirus)
80
what do viruses do to down regulate MHC
viruses make proteins that down regulate MHC class I molecules on infected host cell surface
81
what do tetherin act against
enveloped viruses
82
where does tetherin bind to
Binds to the surface glycoproteins
83
what do tetherin act against
Act against a wide range of viruses (retroviruses; ebolaviruses)
84
what does tetherin prevent
release of the virus while budding
| Retained particles are targeted for degradation
85
what does tetherin trigger
inflammation
86
what is CMV
cytomegalovirus
87
what is Vpu
viral protein U
88
how is tetherin degraded
HIV expresses Vpu, which triggers degradation of Tetherin
89
what is tetherin co-opted for
entry pathway of CMV
90
what does ebola glycoprotein inhibit
inhibits Tetherin association with a viral surface protein
91
what can yeast be
filament
| yeast
92
what does the immune system recognise in fungi
cell wall
93
what is fungi part of
commensal flora
94
what can fungi cause
infection in absence of an effective immune response
95
what do dendritic cells do to fungi
phagocytose fungal cells
96
what peptides are expressed in relation to fungi
MHC class 2
97
what is required for effective immune response against C. albicans
Both CD4 and CD8 T cell
98
how are T cells activated
Need the peptides to be presented by MHC class II on dendritic cells to get activation of T cell response
99
effect of CD8 T cells on fungi
CD8 T cells been shown to inhibit fungal cell growth
100
what can help clear fungi infection
innate immune system
101
what are the main four divisions of protozoa
flagellates
amoebas
ciliates
sporozoa
102
what causes malaria
Plasmodium falciparum
103
where do plasmodium falciparum replicate
can only replicate in erythrocyte
104
effect of antibodies on Plasmodium falciparum
can inhibit uptake into erythrocytes and hepatocytes
105
how does erythrocytes differ
Erythrocytes naturally don’t have MHC class I on surface (un-nucleated cells)
106
effect of Plasmodium falciparum
down regulate T helper cytokines
107
what is virulence mainly associated with
immune evasion
108
what are polymorphic proteins
immunologically distinct
109
what does Plasmodium falciparum cause
highly polymorphic surface proteins
110
what is there a lack of in Plasmodium falciparum
Lack of MHC class I on RBC’s protect from CD8 T cells
111
What are the immune attack
Opsonising antibodies
Complement deposition
Invasion blocking antibodies
112
What does opsonising antibodies lead to
Phagocytosis
113
What does complement deposition lead to
Phagocytosis
| Lysis
114
What are the immune evasion strategies
Varying sequence while maintaining function
Redundancy in multi-gene families
Reduced antigenicity
115
what is trypanosomiasis
sleeping sickness
116
what is trypanosma brucei like
extracellular
117
what protects against trypanosma brucei
Variant surface proteins to protect from immune system
118
what can dampen inflammatory response
Saliva from infected tsetse fly
119
what are helminths
Worms that live like parasites
120
what are helminths like
Mostly extracellular, move to organs
121
what is the immune system problem with helminths
cannot phagocytose them
122
what are the symptoms of Schistosoma mansoni
Diarrhoea, blood in faeces, organ damage
123
what is Schistosoma mansoni associated with
chronic (long term) disease
124
what does Schistosoma mansoni have to protect against
both eggs and adult worms
125
what does Schistosoma mansoni cause
Venous blood release of eggs into environment
| Granuloma formation to contain eggs
