HIV Flashcards
How is HIV transmitted?
Bodily secretions (STI)
Infected blood (intravenous drug use)
What happens during the first 2-6 weeks of an HIV infection?
Sometimes patients have flu-like symptoms
CD4 T cell levels dip below 500 cells/mL
What is the asymptomatic phase of HIV?
Seroconversion
CD4 T cell levels slowly decline over 2-20 years
What is seroconversion?
Antibodies to virus are present in serum
What is the symptomatic phase of HIV?
CD4 T cell levels dip below 500 cells/mL and opportunistic infections take hold
What is AIDS?
When CD4 T cell levels reach 0 cells/mL and quickly results in death
What does the membrane surface of HIV carry?
Envelope glycoprot3eins
What does each capsid in HIV carry?
Two RNAs and reverse transcriptase which copies RNA into DNA
Where does HIV undergo fusion?
At the cell membrane
What does HIV bind to on the T cell?
CD4 and a chemokine co-receptor
What happens when the viral envelope fuses with the cell membrane?
The capsid uncoats itself and the viral genome enters the cell
What does an HIV-1 envelope glycoprotein contain?
Conserved regions
Variable regions
Fusion peptide
The extracellular part of the protein is gp120 while the intracellular part is gp41
What type of people are resistant to HIV infections?
People with a mutation in CCR5
What cell types of infected by HIV?
Cells that have CD4 and the chemokine receptor
What is an alternate chemokine receptor that HIV can bind to?
Cxcr4
What exposes the CCR5 receptor binding site?
HIV gp120 binding to CD4 which causes a conformational change
What does HIV binding to the co-receptor induce?
A second conformational change exposing the fusion peptide
What does reverse transcriptase do?
Copies the ssRNA into dsDNA
What does integrase do?
Inserts DNA into the genome as a provirus
What is the significance of HIV being error-prone?
It can tolerate all sorts of mistakes and continue to synthesis DNA
What is NFkappaB turned on by?
The activation of infected T cells or macrophages
What does T cell activation induce (HIV)?
Low-level transcription of provirus
What does the Tat gene do?
Amplifies transcription of viral RNA
What does the Rev gene do?
Increases transport of singly spliced or unspliced viral RNA to the cytoplasm
What are Gag, Pol, and Env proteins translated and assembled into?
Virus particles which bud form the cell
