HIV & AIDS

Question 1

Which HIV virus is largely confined to Africa, with less efficient transmission and non-pandemic?

Answer 1

HIV-2

Question 2

What is the significance of HIV-2?

Answer 2

HIV-2 may confer some immunity to HIV-1

Question 3

How does HIV initially attach to cells?

Answer 3

gp120 binds to CD4 molecule

Question 4

What else must HIV do to attach to cells?

Answer 4

Must bind to chemokine receptors - i.e. CCR5 or CXCR4

Question 5

How does the HIV virus enter the cell once attached?

Answer 5

Fusion of viral and cell membranes occurs following sequential interaction of gp120-CD4 + co-receptor binding.

Then, interaction of fusion domain of transmembrane protein gp41***

Question 6

How does the HIV virus replicate?

Answer 6

Viral cDNA synthesis via REVERSE TRANSCRIPTION.

Question 7

What is the significance of HIV replication via reverse transcriptase?

Answer 7

Reverse transcriptase does not correct for errors, and produces lots of errors. This causes a high number of mutations in HIV replication.

Thus, HIV is resistant to anti-retrovirals and also difficult to produce vaccines for.