Human immunodeficiency virus Flashcards
transmission
contact with bodily fluids: blood, semen, vaginal secretions and breast milk
* sex
* infection drug use
* mother-to-child
features of retrovirus
contain RNA genomes that get reverse transcribed into DNA
* virus genomes permanently integrate into the host genome as a provirus
morphology
diploid: 2 identical copies of (+) ss RNA
gp120
binds to CD4 receptor and a chemokine co-receptor on host cell (attachment)
gp41
facilitate fusion of viral and cell membranes
3 activities of reverse transcriptase
- DNA synthesis from the RNA template
- Ribonuclease H (RNA degradation)
- DNA-dependent DNA synthesis
establishes
latency
replication
cell transcribes provirus into mRNA
* HIV genomic RNA
* mRNA is translated inot long protein chains
assembly
viable HIV virions released by budding
* as CD4+ T cells die, host becomes vulnerable to opportunistic infections
what are the main cellular targets of HIV?
- M- tropic (“R5”) HIV strains
- T-tropic (“X4”) HIV strains
M-tropic (“R5”) HIV strains
typically infects macrophages
use CD4 and CCR5 receptors
* predominate early in infection
T-tropic (“X4”) HIV strains
infects only CD4+ T cells
Use CD4 and CXCR4 receptors
* predominate later in an infection
stage 1
acute/primary HIV infection
stage 2
clinical latency
stage 3
acquired immunodeficiency syndrome (AIDS)
