Chapter 6: Lecture 3 (HIV) Flashcards
How is HIV transmitted in sexual transmission?
Mucosal barrier (anal or vaginal) is breached
- virus enters bloodstream
- infects mucosal dendritic cells
What family does HIV belong to?
Retrovirus
Lentovirus
What is HIV’s capsid protein?
p24
What are HIV’s glycoproteins?
gp120: outer part
gp41: transmembrane
What are some important HIV viral enzymes?
Protease
Reverse transcriptase
Integrase
What does LTR part of HIV do?
Initiates transcription
-binds to transcription factors
What does the gag part of HIV do?
Encodes for proteins inside the virus (e.g. p24)
-protein shell enclosing genetic material
What does the env part of HIV do?
Encodes for glycoproteins (e.g. gp 120 and 41)
What does the pol part of HIV do?
Encodes for viral enzymes (e.g. reverse transcriptase)
How does the HIV virus enter the cell?
1) Chemokine receptors CCR5 and/or CXCR4 target CD4 cells
2) gp120 binds to CD4 cell
3) gp41 promotes membrane fusion
How does the HIV virus replicate?
1) Reverse transcriptase synthesizes proviral dsDNA from original RNA
2) Integrase inserts proviral DNA sequence into host genome
3) Host cell activation triggers LTR to initiate transcription
Antigenic stimulation causes a release of what?
NF-kB
What does NF-kB normally do?
Upregulate T cell response
What does NF-kB do in HIV infected cells?
Initiate transcription via LTR
What is responsible for host cell death?
- Viral replication
- Pyroptosis: programmed death pathway
Other than CD4 cells, what other cells can HIV infect?
- Macrophages
- Dendritic Cells
- Microglia
How does HIV infection affect B lymphocytes?
- Lymphoma
- Non specific hypergammaglobulinemia
- Impaired humoral immunity (reduced isotype switching and reduction in antibody production)
Where does HIV normally stay and replicate during latent period?
Lymph nodes
-Dendritic cells transport virus to CD4 cells there
What happens when HIV is spreading throughout body?
Viremia
By when can a viral load of HIV be detected?
Day 7-14
By when can p24 antigen be detected?
Day 16
By when will most people be antibody positive for HIV?
Day 28
What is the first detectable test for HIV?
NAT: tests for viral RNA by day 10
What are the symptoms of acute retroviral syndrome?
HIV viremia (self limited)
- fever
- sore throat
- muscle aches
