Flashcards in Retroviruses Deck (21):
encode RNA-dependent DNA polymerase (reverse transcriptase[RT])
-Oncovirinae (HTLV-1,2,5); Cancer, neurological disorder
-Lentivirinae (HIV-1, HIV-2); slow, neurological disorders, immunosuppression
-Endogenous viruses; retrovirus sequences that are integrated in the human genome (up to 8%)
2 identical copies of +RNA
HIV virion structure
Binds CD4 on T cells
also binds CCR5 on certain T cells
Fusion though gp41
HIV Early Phase Replication
entry by fusion, genome release
RT makes complementary -DNA, then synthesizes +DNA, enters nucleus and is integrated into host genome by intergrase
HIV Late Phase Replication
Full length RNA produced, which then makes mRNAs and proteins for new virion.
Envelopment and release at plasma membrane or through syncytia. HIV does not have to kill cell. requires cleavage of Gag and Gag-Pol
M (most common)
HIV evasion tactics
infection of Lymphocytes and Macrophages (inactivates key parts of immune defense)
CD4 T cell infection (syncytia,apoptosis, loss of activation and control of immune system)
Direct cell to cell spread
1: Acute infection: resembles flu + rash
2: Persistence: Chronic Lymphadenopathy +fever, weight loss, fatigue
3:Reduction in CD4 T Cells <500/uL (increased virus in blood)
After Stage 3?
CD4 T Cell count <200/uL
Virus load >75,000 copies/mL
Th17 depletion leads to fungal and bacterial infection
Th1 depletion leads to viral and intracellular bacterial infections
one of the most devastating epidemics ever.
HIV progresses from asymptomatic to profound immunosuppression called "AIDS"
-direct effect of HIV on CNS
Drug users, many partner sex, prostitutes, newborns of infected mothers, blood and organ transplant pre-1985
ELISA, western blot, Virion RNA RT-PCR, Real-time RT-PCR, CD4 cell counts + CD4:CD8
Many Many options, combinations for less chance of resistance.
Highly Active Antiretroviral Therapy very important
education on safe sex, blood +organ donation screening, antiviral drugs, sterile needles.
primary targets are different between clades and species.