CMB1003/L14 HIV

Question 1

In 1981, there was a prevalence of which 2 diseases within the male homosexual population?

Answer 1

Pneumocystis
Kaposi’s sarcoma

Question 2

How is HIV transmitted?

Answer 2

Through bodily fluids

Question 3

What disease does HIV-1 cause?

Answer 3

AIDS

Question 4

Both HIV-1 & 2 are closely related to which virus?

Answer 4

Simian immunodeficiency virus (SIV)

Question 5

What is the likely origin of HIV?

Answer 5

From butchering of primates for food

Question 6

Describe the spread of 1920’s Kinshasa. (6)

Answer 6

Major expansion
Increased industry
Increased male population
More sex workers
More STIs
More needles for treatment

Question 7

Describe the structure of the HIV virus. (5)

Answer 7

+ve ssRNA
RT and integrase enzymes
Packaged in a vase-shaped P24 capsid
Wrapped in a P17 matrix protein
Wrapped in an envelope with GP41/GP120 surface glycoproteins

Question 8

Describe how the HIV virus infects human cells. (8)

Answer 8

Glycoprotein interacts with CD4 receptor on macrophage and T cells
Opens CCR5 receptor
Fusion from without
RT - RNA dep DNA pol. synthesises complementary -ve ssDNA
RT - RNase breaks down ssRNA
RT - DNA dep RNA pol. synthesises +ve DNA
Integrase targets LTRs to integrate into host cell chromosome

Question 9

Describe how HIV exits the host cell. (5)

Answer 9

Host cell becomes activated
DNA from viral genome is replicated into mRNA and ssRNA
mRNA leaves nucleus into ER
Translated into polyproteins and spliced
All components integrated into budding particles

Question 10

Which proteins are spliced from the polyprotein made in the ER from the viral genome? (3)

Answer 10

gag - P17 & P24
pol - RT & integrase
env - GP41 & G120

Question 11

Describe the common features of the retrovirus family. (4)

Answer 11

Reverse transcriptase
Wasting
Immunodeficiency
Dementia

Question 12

What do activated CD4 T cells do in response to HIV? (3)

Answer 12

Activate B cells to create antibodies
Activate CD8 cytotoxic T cells to kill virally infected cells
Activate NFkB which activates genes involved in immune response and HIV/RNA integrated into host cell chromosome

Question 13

Name 3 opportunistic infections associated with HIV-1 infection.

Answer 13

Pneumocystis sp.
TB
Malaria
Candida sp.
Toxoplasma sp.
HPV

Question 14

Give 2 examples of reactivation of latent infections.

Answer 14

Varicella zoster - shingles
Epstein Barr - B-cell lymphomas
Cytomegalovirus - lymphomas
HSV-8 - Kaposi’s sarcoma

Question 15

Give 3 challenges of HIV vaccines.

Answer 15

Mutation rate
Mucosal infection
No good animal model

Question 16

What is triple therapy? (3)

Answer 16

Highly active anti-retroviral therapy (HAART)
Nucleoside analogues - competitive inhibitor of RT
Peptide analogues - competitive inhibitor of HIV protease

Question 17

Describe anti-CCR5 therapy.

Answer 17

Blocking CCR5 or bone marrow transplant from CCR5 defective individuals