S47(2) HIV Life Cycle

Question 1

HIV Life Cycle

Step 1

Answer 1

HIV binds to CD4 receptor and CCR5/CXCR4 co-receptor of immune cells

Question 2

HIV Life Cycle

Step 2

Answer 2

Fusion of HIV with host immune cell

Question 3

HIV Life Cycle

Step 3

Answer 3

Reverse transcriptase turns the RNA virus into DNA (NRTIs and NNRTIs work here)

Question 4

HIV Life Cycle

Step 4

Answer 4

Viral DNA is incorporated into host DNA through integrase (INSTIs work here)

Question 5

HIV Life Cycle

Step 5

Answer 5

Normal transcription and translation processes produce viral RNA and proteins (PIs work here)

Question 6

HIV Life Cycle

Step 6

Answer 6

Viral RNA and proteins bud off from the host cell

Question 7

HIV Life Cycle

Step 7

Answer 7

Matures into a virion; immune cell eventually lyses

Question 8

Immune cells with CD4 receptors: T-cells, macrophages, monocytes, and dendritic cells

Answer 8

True

Question 9

Infection period

Answer 9

first 2-8 weeks
Sharp increase in viral load
Decrease in CD4 count

Question 10

Months 1-3 after infection

Answer 10

seroconversion
CD4 increase
viral load decreases

Question 11

years 2-12 after seroconversion

Answer 11

asymptomatic and symptomatic period

Question 12

1-3 years after sypmptomatic period

Answer 12

AIDS

Leads to death

Question 13

Stages of Infection

Acute HIV Infection

Answer 13

Flu- like symptoms or symptomatic

High viral load

Question 14

Stages of Infection

Chronic HIV Infections

Answer 14

Asymptomatic/ clinical latency
HIV reservoirs
Can transmit if viral load not undetectable

Question 15

Stages of Infection

AIDS

Answer 15

Preventable with treatment
CD4 < 200
Prone to OI

Question 16

Viral Diagnosis
NAT – nucleic acid test -> viral load

4th generation test:

• IgG, IgM, p24 antigen
• 99% sensitive, 99% specific

Answer 16

Window period – time between exposure and detectable infection ~ 2 – 3 weeks

Question 17

First reliable marker for infection

Answer 17

~ day 12

Question 18

HIV Capsid p-24

Answer 18

~day 15

Question 19

IgM antibody

Answer 19

~ day 20

Question 20

IgG antibody

Answer 20

~ day 30

Question 21

Viral Monitoring

Answer 21

Viral load
Goal = undetectable (UD)

CD4 count
Goal > 200 copies/mL

Question 22

Treatment Naïve Design

Answer 22

ALWAYS 3 drugs
2 of the 3 MUST be a NRTI – BACKBONE of regimen
Don’t repeat nucleotides

Start AS SOON AS POSSIBLE

Use a back up method for the first 6 months and until viral load < 200 copies/mL