S47(2) HIV Life Cycle Flashcards
HIV Life Cycle
Step 1
HIV binds to CD4 receptor and CCR5/CXCR4 co-receptor of immune cells
HIV Life Cycle
Step 2
Fusion of HIV with host immune cell
HIV Life Cycle
Step 3
Reverse transcriptase turns the RNA virus into DNA (NRTIs and NNRTIs work here)
HIV Life Cycle
Step 4
Viral DNA is incorporated into host DNA through integrase (INSTIs work here)
HIV Life Cycle
Step 5
Normal transcription and translation processes produce viral RNA and proteins (PIs work here)
HIV Life Cycle
Step 6
Viral RNA and proteins bud off from the host cell
HIV Life Cycle
Step 7
Matures into a virion; immune cell eventually lyses
Immune cells with CD4 receptors: T-cells, macrophages, monocytes, and dendritic cells
True
Infection period
first 2-8 weeks
Sharp increase in viral load
Decrease in CD4 count
Months 1-3 after infection
seroconversion
CD4 increase
viral load decreases
years 2-12 after seroconversion
asymptomatic and symptomatic period
1-3 years after sypmptomatic period
AIDS
Leads to death
Stages of Infection
Acute HIV Infection
Flu- like symptoms or symptomatic
High viral load
Stages of Infection
Chronic HIV Infections
Asymptomatic/ clinical latency
HIV reservoirs
Can transmit if viral load not undetectable
Stages of Infection
AIDS
Preventable with treatment
CD4 < 200
Prone to OI
Viral Diagnosis
NAT – nucleic acid test -> viral load
4th generation test:
- IgG, IgM, p24 antigen
- 99% sensitive, 99% specific
Window period – time between exposure and detectable infection ~ 2 – 3 weeks
First reliable marker for infection
~ day 12
HIV Capsid p-24
~day 15
IgM antibody
~ day 20
IgG antibody
~ day 30
Viral Monitoring
Viral load
Goal = undetectable (UD)
CD4 count
Goal > 200 copies/mL
Treatment Naïve Design
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
