escape strategies Flashcards

1
Q

what are the 6 types of escape strategies

A

Hiding, interfering, destroying, virulence factors, mutations, disrupting

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2
Q

describe the hiding cell escape strategy

A

hides from the immune system by residing within cells
can lay dormant for years
individual will be asymptomatic
will emerge once resistance is lowered
example = HPV

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3
Q

describe the interfering cell escape strategy

A

they interfere with the function of the immune system by blocking signals
example = anthrax
secretes 3 different proteins (protective antigen, lethal factor and oedema)
supresses pro-inflammatory cytokine secretion which prevents the inflammatory response

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4
Q

describe the destroying cell escape strategy

A

they destroy elements of the immune system (e.g. APC peptides)
example = small pox
-secretes proteins which inhibit complement enzymes
- which interferes with MHC class 1 proteins

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5
Q

describe the virulence factors cell escape strategy

A

they use virulence factors to destroy or cause malfunction of host cells.
example = chlamydia trachomatis
- doesn’t need to invade host cell, instead secretes toxins and virulence factors
- these make influence membrane channels and deliver anti-host factors into the cell
- which leads to apoptosis (cell death)

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6
Q

describe the mutations cell escape strategy and the 2 types

A

they generate escape mutations to avoid being a target of cytotoxic t cells
Antigenic drift and antigenic drift

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7
Q

what is antigenic drift

A

point mutation in genes code for immunogenic glycoproteins on the surface of the virus - leads to change in presentation - lack of recognition from the body

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8
Q

describe the disrupting cell escape strategy

A

they disrupt complement pathways, phagocytosis, innate immune receptors and adaptive immune response

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8
Q

what is antigenic shift

A

the alteration of the surface of an antigen by combining 2 different strains - leads to different presentation

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9
Q

what is a virulence factor

A

molecules or traits that help pathogens infect or damage their hosts

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10
Q

what is an example of a virulence factor a pathogen could adapt to avoid phagocytosis

A

A capsule around its self - this creates a larger SA making it more difficult to be engulfed and recognised

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11
Q

how does Yersinia spp use virulence factors to cause immunosuppression

A

it secretes virulence antigen LcrV
- this then signals to TLR2 dependant signalling to stimulate IL-10 secretion
- this leads to immunosuppression as IL-10 is an anti-inflammatory cytokine inhibiting the activity of NK cells and macrophages impeding immunopathology

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12
Q

what are the multiple escape mechanisms of HIV

A

hiding
hijacking through immunosuppression - they replicate in CD4+ cells leading to cell death
- this degrades the hosts ability to mount a strong cell mediated response
- it also increases the body’s susceptibility to other infections
Destruction - targets C type lectin on dendric cells to skew the T cell response

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13
Q

how does tumour evasion work

A

they avoid recognition by masking their antigens with a thick outer coat
- increase Treg counts to counteract an immune response
- secrete factors to promote angiogenesis to improve circulation and enhance tumour growth
- has a high rate of genetic mutation and deletion

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14
Q

why do tumours secrete TGF-B during evasion

A

to inhibit the proliferation of lymphocytes

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15
Q

what is immunotherapy

A

-the use of a persons own immune system to fight things like cancer cells
-is treatment of a disease with therapeutic agents to that promotes or inhibits the immune response

16
Q

what immune mediated actions are used to treat myeloma

A
  • complement dependant cytotoxicity
  • antibody dependant cell-mediated cytotoxicity
    -antibody dependant cellular phagocytosis
    Daratumumab is a synthetic antibody which attaches itself to the protein CD38 on the surface of myeloma making it more visible to the immune system
17
Q

how does Daratumumab help treat myeloma

A

Daratumumab is a synthetic antibody which attaches itself to the protein CD38 on the surface of myeloma making it more visible to the immune system

18
Q
A