L68 Flashcards Preview

Viruses & Parasites > L68 > Flashcards

Flashcards in L68 Deck (35):
1

What is the family & genus of HIV?

Family = retrovirus (RNA --> DNA)
Genus - lentivirus (long incubation time)

2

What does a high error rate of reverse transcriptase yield?

HIV evolution --> drug resistance

3

What are the 2 important proteins of the HIV envelope?

Gp120 + gp41 = spike
(Coded from env)

4

What is gag p17?

Matrix
Lines inner leaflet of envelope

5

What is gag p24?

The capsid that encloses HIV RNA + enzymes + proteins

6

Which enzymes are carried with HIV in active form?

= regulatory proteins
1. Reverse transcriptase - to code DNA once inside host cell
2. Integrase - follows RT
3. Protease - was used to mature the virion after budding

7

What is the diagnostic marker used to measure the effectiveness of anti-retroviral therapies?

HIV RNA
gag p24 (capsid)

8

What part of HIV is the therapeutic target?

The enzymes!
Kill these - make the virus ineffective

9

What are modes of HIV transmission?

Sex
During birth
Needles! IVDUs

10

How does HIV get into tissues?

1. Break mucosal epi barrier
2. Transcytosis
Either way = bad b/c 1st responder likely to be CD4 = infection target

11

How does HIV attach to host cells?

Gp41/120 spike + CD4
Conformational change --> membranes together

12

What is required for HIV-host membrane fusion?

Co-receptor binding (by different part of gp120)
CCR5 and/or CXCR4
- Found on macrophages & T cells (cell trophism)
MEANS that entry requires TRIMER formation: gp41/120 + CD4 + co-receptor

13

What is the pre-integration complex vs provirus?

Pre-integration complex = how enters nucleus w/ integrase
Provirus = after in host DNA

14

How can genetics or drugs affect HIV by working at CCR5?

Genetics:
- Mutated --> no CCR5 fxn but also no HIV co-receptor needed for binding
Drug target - Maraviroc

15

What are the 3 types of RT inhibitors?

Nucleoside analogs
NucleoTIDE analogs
Non-nucleoside analogs
All 3 change RT's fxn = X RNA --> DNA

16

What are HIV long terminal repeats (LTRs)?

Identical RNA on both ends (5 & 3') of the genome
Used for integration

17

Where do transcription factors that regulate expression of viral genes bind?

@ 5' LTR

18

What are the 3 classes of RNA molecules produced during viral replication? Which are packaged into the virus?

2kb, 4kb - 9kb into new virus

19

Which RNA protein is used to make the initial HIV diagnosis?

gag p24

20

What are the 3 structural genes on the RNA genome?

Gag (non-envelope membranes)
Pol (polymerases)
Env (envelope)

21

What 2 proteins are coded for by the gag gene?

gag p24 = capsid
gag p17 = matrix, lines inner leaflet of viral envelope

22

What 3 proteins are coded for by the pol gene?

RT
Integrase
Protease

23

What 3 proteins are coded for by the env gene?

gp 120 & 41

24

What are the 2 regulatory genes of the HIV genome?

Tat - needed for initiation & elongation starting at 5' LTR
Rev - transports new virion RNA into the cytoplasm

25

What are the 4 accessory proteins/genes on the HIV genome?

nef
vpr
vpu
vif
As a group, remove restriction factors that host cell uses to stop DNA replication when senses infection

26

Which cells can HIV target to change function and create immune deficiency?

CD 4 & CD8 T cells
B cells
Myeloid DCs
Plasmacytoid DCs
Uninfected bystander cells

27

What is pyroptosis?

HIV induced cell death that is VERY inflammatory
Recruits other immune cells --> prime for infection

28

What is the viral load?

In acute infection, when virus in plasma peaks

29

What is the viral set point?

When CD8 response rises to control viral replication
- Allows recruitment of Ab response

30

How can HIV infected cells kill uninfected bystanders?

Infected - normal
CD95L - CD95
gp41/120 - CD4/CXCR4 death signals

31

Which 2 cytokines have anti-HIV properties?

IL10
IFNg

32

Which HLA subtypes have natural protection against HIV?

B 27 & 57

33

Describe the T cell HIV vaccine.

Infect APCs to present HIV to T cells --> create stronger immune response if the virus actually presents
Problem = Too late, could have already est infection in APCs
More therapeutic

34

Describe the B cell HIV vaccine?

Abs vs gp 41/120 - no initial binding & prevent 1ary infection
Problem: HIV variation & getting Abs that are long lasting in high [ ]s

35

What are the 2 major HIV vaccine trials?

STEP = T cell vaccine, failure, increased infection
RV144 Thai = B cell vaccine, saw 31% less infection