Lecture 13 Flashcards

1
Q

There is a decline in infection from 2001 as a result of

A

anti-retroviral therapy - reduces infectiveness

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2
Q

Circumcision protects men from HIV by about __%

A

70%

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3
Q

HIV is part of the retroviral family of _________

A

Lentiviridae, meaning they cause infection slowly

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4
Q

SIV is

did HIV arise from it?

A

Simmian Immunodeficiency virus

HIV arise from these monkey viruses

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5
Q

The slaughtering of monkeys in africa likely lead to the ______ of HIV variants into humans in the 1930s

A

Zoonoses

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6
Q

SIV, HIV1/2 all have regulatory proteins __, __, ___

But differ in the variable regions of regulatory proteins

A

SIV, HIV1/2 all have regulatory proteins gag, pol, env

But differ in the variable regulatory proteins

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7
Q

There are _ single strands of RNA in the HIV virus

A

2

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8
Q

Env = gp 120 and …

A

gp120 (Surface; cell attachments) and

gp 41 (Transmembrane fusion domain)

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9
Q

gag consists of

structural proteins

A
  • p17 (MA - Matrix)
  • p24 (CA-capsid)
  • p7 (Nucleocapsid)
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10
Q

pol consists of

A

p66/51 (RT-reverse transcriptase)

p32(IN- integrase)

p11 (PR - protease)

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11
Q

clades are seperated by their…

A

genetic diversity

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12
Q

HIV -1 M groups sits close to….

A

SIV CPZ

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13
Q

gp120 binds to ____

A

CD4

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14
Q

Once it binds, the envelope undergoes a conformational changes and binds a second time to _____ and _____

A

Once it binds, the envelope undergoes a conformational changes and binds a second time to CCR5 or CXCR4 co receptors

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15
Q

Upon entering the cell, the RNA undergoes _____ _______

A

reverse transcription

makes pro-viral DNA and integrates to the host DNA

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16
Q

what are the key features for HIV replication?

A

Rapid

Error prone reverse transcriptase leads to rapid evolution of multiple quasispecies

10 billion particules produced per day

17
Q

If Virus enters an activated CD4+ cell - it is..

If resting…

A

killed

If resting - latency

18
Q

True or False

HIV can only affect Cd4+ T cells

A

False

Can also infect Monocyte/macrophages

19
Q

Viruses that use CCR5 are called

A

R5 viruses (95%)

20
Q

Viruses that use CXCR4are called

A

X4 viruses

21
Q

R5 viruses cause ___ T-cell destruction

22
Q

50% of patients with AIDS carry an __ virus

A

X4 virus (develops later on)

23
Q

If you are homozygous for CCR5, you are only exposed to rare infection with ___

24
Q

True or False

CCR5 is not neccessary for immune function

25
True or false HIV can enter Dendritic, Thymocytes and CD34+ progenitor cells
true
26
What is the normal role of APOBEC3G? Which HIV protein blocks it?
Sees foreign RNA and edits so it doesn't persist in the cell. Blocked by vif (HIV protein)
27
What is the normal role of Trim 5 alpha? Which HIV protein blocks it?
Blocks uncoating of retroviruses Blocked by capsid
28
What is the normal role of Tetherin? Which HIV protein blocks it?
Blocks release of virus blocked by vpu
29
What is the normal role of LEDGF? Which HIV protein facilitates integration?
Tethes HIV to host chromatic Integrated by Integrase
30
How does HIV evade the immune response?
Sequence variation - Lack of recognition Altered antigen presentation - down regulation of MHC class I molecules by Tat, Vpu and Nef Loss of effector cells - Clonal exhaustion, loss of CD4 Tcell help, Replicative senescence Latency - silent, evades response Priveleged sites of viral replication - BB barrier etc...