HIV Virology (lecture)

Question 1

HIV is ________ (enveloped/nonenveloped), _____ (ds/ss), ______ (DNA/RNA) virus.

Answer 1

enveloped, ss, RNA

Question 2

What is the docking glycoprotein of HIV?

Answer 2

gp120

Question 3

What cell classification is the initial infection target of HIV?

Answer 3

APCs (dendritic cells, langerhans, macrophages)

Question 4

Why are females more susceptible to HIV contraction than men during vaginal intercourse?

Answer 4

There is a high [APC] in vaginal mucosa when compared to the penis.

Question 5

A _________ (circumscribed/uncircumscribed) male has a higher risk of infecting their partner?

Answer 5

Uncircumscribed - the highest concentration of HIV is found in the frenulum

Question 6

What is the site of initial viral replication of HIV?

Answer 6

local lymph nodes

Question 7

During the clinically latent period viral load is roughly ______ (stable/declining/increasing) and CD4 count is roughly ________ (stable/declining/increasing).

Answer 7

stable, declining

Question 8

What are the binding patterns of HIV to CD4 cells?

Answer 8

HIV - gp120 to CD4 on T cell

HIV - gp120 co receptor to CCR 5 / CXCR 4 on T cell

Question 9

What is the role of gp 41 in HIV infection?

Answer 9

It first tightens the adhesion after gp 120 and co receptor binding, then facilitates fusion of the HIV virion and CD 4 cell by folding in on itself.

Question 10

What is the role of Vpr in infection?

Answer 10

It facilitates HIV DNA (post reverse transcriptase) transport to the nucleus.

Question 11

What specific step of HIV infection results in life long infection of a T cell and what protein inherent to HIV is responsible for this step?

Answer 11

Integration (performed by integrase) into the host cell DNA results in that cell’s life long infection.

Question 12

What role does Vpu play in HIV infection?

Answer 12

It degrades CD4 and tetherin, resulting in avoidance of a cells auto infection.

Question 13

What are the 8 steps in HIV replication and the major proteins involved in each (where applicable)?

Answer 13

1. Attach/enter: gp 120, gp 41 bind to CD4 and CCR5/CXCR4
2. Uncoding RNA –> DNA: Reverse transcriptase
3. Transport to nucleus: Vpr
4. Integration into host DNA: Integrase
5. Transcription of Host + HIV DNA
6. Translation of host + HIV RNA
7. Assembly of HIV: Nef
8. Release: Protease

Question 14

What are the screening and diagnostic tests for HIV infection?

Answer 14

Screening: ELISA
Diagnostic: Western Blot (must have all proteins tested)

Question 15

About how long does it take to seroconvert post HIV infection?

Answer 15

A couple of months

Question 16

What are the 4 steps of HIV infection that are targeted by Rx?

Answer 16

1. Cell entry
2. Uncoding
3. Integration
4. Protease