Lec 11 - HIV Infection Flashcards

1
Q

which cells do HIV virus target mainly

A

cd4 T cells

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2
Q

3 phases of hiv/aids

A

acute
asymptomatic
development of aids

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3
Q

initially, where are the most cd4 t cells lost

A

30-60%
lost in gut associated lymphoid tissue

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4
Q

what type of HIV virus predominates early on

A

CCR5

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5
Q

why does virus become more ehterogenous during asymptomatic phase

A

Virus population becomes more heterogeneous due to accumulated mutations

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6
Q

rate that CD4 cells reduce at in asymptomatic/ year

A

60,00/ml/year

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7
Q

where does virus replicate during asymptomatic phase

A

continues in lymph nodes and lymphatic tissue
(dendritic cells will also interact with virus, but virus cant replicate in these)

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8
Q

where is the latent resovoir of virus

A

in quiescent memory t cells

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9
Q

definition of aids

A

<200 T cells/ml plasma

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10
Q

what type of HIV virus predominates during AIDS

A

CXCR4

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11
Q

name of idnividuals that never progress to aids

A

elite controllers
(rare)

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12
Q

what do dendritic cells do

A

Dendritic cells in mucosa bind HIV shed by macrophages and deliver it to CD4+ T cells in lymph nodes

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13
Q

what part of dendritic ccell binds to gp120

A

DC SIGN

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14
Q

4 steps of virus binding to on CD4 cell

A
  1. binds heparin sulfate
  2. GP120 binds to CDV4
    = conformational change!
  3. coreceptor binds CCR5
    or
    CVCR4
  4. fusion protein delivers viral capsid into cell
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15
Q

where does reverse transc occur

A

inside the capsid

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16
Q

what viral protein allows newly formed dsDNA to enter nucleus

A

VPR
and integrase embeds into the genome

17
Q

what does integrase do

A

removes 2 base pairs on each end to give overhang = sticky ens

18
Q

what is viral dna transcribed by

A

host RNA polymerase II

19
Q

2 ways CD4 t cells are killed

A

apoptosis or pyroptosis

20
Q

what triggers apoptosis

A

when virus enters ACTIVE cell
= triggers caspase 3

21
Q

what triggers pyroptosis

A

virus infects a quiescent cell
= caspase 1 activated
= pores in memb so the cell bursts
= IL-1 released

22
Q

what triggers caspase 1

A

build up of reverse transcription byproducts
= detected by IFI16 = which activates caspase 1

23
Q

how can HIV hide from immune system whilst it moves from cell to cell

A

doesnt just exocytose
moves cell to cell

24
Q
A