HIV infection

Question 1

CD4 T cells decrease on average by how much each year in an infected person

Answer 1

50 cells/mm3 per year

Question 2

normal CD4 count is

Answer 2

500

Question 3

When are the two peaks of RNA HIV copies during lifetime course

Answer 3

At start of the infection and very end - when CD4T cell count very low

Question 4

Define AIDS

Answer 4

1) presence of an HIV infection

2) an opportunisitic infefction OR 2) CDT cell count <200

Question 5

Which surface protein is needed for viral entry?

Answer 5

gp120

Question 6

2 co-receptors are essential for entry

Answer 6

CCR5 and

CXCR4

Question 7

what type of cells can HIV infect

Answer 7

CD4 T cells (always need a coreceptor)

macrophages, monocytes can also be infected

Question 8

Ligand for CXCR4 is

Answer 8

SDF-1

Question 9

Ligand for CCRC5 is

Answer 9

MIP1-alpha MIP-1 beta

Question 10

Homozygotes for which coreceptor are resistant to infection

Answer 10

CCR5 mutations

Question 11

Which pro-inflammatory cytokines increase infectivity of HIV

Answer 11

IL-1
TNF
IL-6

Question 12

which TF binds to the LTR of HIV-1 and enhances its transcription?

Answer 12

NFKB

Question 13

What is the immune deficiency in HIV infection

Answer 13

decrease number and function of CD4 T cells

Question 14

What % of infected CD4T cells in vivo

Answer 14

1/1000 are actually infection

- direct killing of cd4t cells not the only thing

Question 15

what might be the mechanism by which CD T cells are dying

Answer 15

Activation induced cell death

• e.g. by envelop proteins of HIV
• or by LPS translocating in the gut after CD4 T cell death

Question 16

Detecting HIV RNA, DNA and protein are

Answer 16

are not very sensitive ways of detecting virus - lots of false positives

Question 17

Best method of detection of HIV

Answer 17

ELISA - 99.5% sensitive

1-2% false positive rate

Question 18

To eliminate/check the 1-2% false positive

Answer 18

A western blot is performed for gp120/160 and gp41 proteins

gp24 at later infection stages

Question 19

How soon can you detect HIV RNA?

Answer 19

12 days of infection

Question 20

HIV p24 is detected how soon after infection

Answer 20

16 days

Question 21

Antibody needs how many weeks to be detected

Answer 21

4-6 weeks

Question 22

HIV viral load and disease progression are

Answer 22

highly correlated

Question 23

The higher the CD4 count

Answer 23

longer survival