HIV/AIDS

Question 1

What is HIV?

Answer 1

Human Immunodeficiency Virus

Question 2

What is AIDS?

Answer 2

Autoimmunodeficiency Syndrome (leading cause of death by infection)

Question 3

How many people are killed a year by HIV?

Answer 3

~2 million

Question 4

How long can the virus be incubated in the human body for?

Answer 4

Up to 12 years where asymptomatic

Question 5

What was the source of HIV?

Answer 5

Scientists believe chimpanzees were carriers (SIV- Simian Immunodeficiency Virus).
SIV mutated into HIV when hunted for meat.

Question 6

How is HIV transmitted?

Answer 6

Blood plasma
Vaginal/cervical fluid
Semen
Breast Milk- only infectious to babies a weaker immune system.

Question 7

What is the structure of HIV?

Answer 7

120nm in diametre

Contains 9 genes that encode for 15 different proteins.

Question 8

How does HIV infect the cells?

Answer 8

1) HIV gp120 binds to CD4 (T-cell macrophage)
2) CXCR4/CCR5 (receptors on CD4) binds to co-receptor binding site.
3) fusion through gp41 protein channel.
4) nucleocapsid enter cell & RNA released from core protein.
5) RT synthesised (RNA-DNA)
6) RNA degradation by RNase H & dsDNA synthesis.
7) dsDNA translated into nucleus where integrate in host chromosomal DNA.
8) Transcription of HIV mRNA.
9) HIV translated to precursor protein production.
10) precursors cleavage
11) proteins assembled
12) budding & maturation

Question 9

How does HIV destroy the immune system?

Answer 9

1) Cells exposed to cell free or cell-associated HIV-1
2) p53 mRNA in neighbouring cells.
3) Activation of larger p53 pool- induces DNA damage, quicker apoptosis.

Question 10

What is syncytium formation?

Answer 10

In vitro phenomenon which describes the fusion of a virally infected cell with uninfected cells.

Question 11

How does HIV destroy the immune system by CD8 cytotoxic CTL?

Answer 11

‘lethal kissing’
cells touch eachother then infected cell bursts and lyse.
CD8 kills CD4 (master cell of immune system) so when killed = AIDS

Question 12

How can HIV be prevented?

Answer 12

Awareness
Protected sex (80% cases through sexual route)

Question 13

How can HIV be treated?

Answer 13

HAART (Triple therapy)
protease inhibitor
nucleoside analogue (anti-RT)- no bases, just sugar and phosphate.

Question 14

What are the potential targets on the HIV virus?

Answer 14

Inhibit RT
Inhibit integrase
inhibit protease
inhibit fusion

Question 15

When was HIV first identified?

Answer 15

1985