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21 Cards in this Set
- Front
- Back
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retroviruses that cause human disease
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HIV,
HTLV Murine leukemia virus-like virus - linked to prostate cancer |
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HTLV infections
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transmitted in blood and bodily fluids
causes T cell lymphoma and neurological disease |
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classification of retroviruses
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*oncoviruses - transform cells in culture and cause cancer
*lentiviruses- slow developing; chronic infections *Spumaviruses - "foamy" appearance; no human disease associated |
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important features of (all) retroviruses
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pos stranded RNA
enveloped ***encode reverse transcriptase - converts RNA into double stranded DNA |
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retrovirus genome
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positive stranded RNA
exists as dimer (2 copies) tRNA bound at pbs - serves as primer for reverse transcriptase gene order: gag-pol-env can be simple or complex (complex have extra peptides) |
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genes of retrovirus code for...
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gag- structural proteins
pol- reverse transcriptase (and integrase) env- envelope |
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Retrovirus
VIRION |
IMMATURE made using polyproteins
not infectious maturation requires cleavage by protease MATURE is infectious |
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HIV
entry/receptors |
requires two proteins on host cell
- CD4 - chemokine co-receptor = CCR5 (T cells) or CXCR4 (macrophages) so infect ore T cells and accelerate disease progression with time |
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Reverse Transcriptase
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allows retrovirus to keep its promoter
prone to errors, so retroviruses have a high rate of mutation |
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Retrovirus
Consequences of Integration |
Irreversible
offspring are infected may lead to tumors |
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Retrovirus
Antiviral targets |
maturation
fusion reverse transcription integration |
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Retrovirus
Positive aspects/uses |
gene therapy
placenta formation amylase in saliva |
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major reason retroviral infections are so difficult to eliminate
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Nuclear Entry of RT complexes
and Integration |
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Retrovirus
Mechanism of virus-induced oncogenesis |
oncogene capture
proviral insertion |
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Types and subtypes of HIV
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HIV-2
from sooty mangabees W. Africa lower viral loads HIV-1 from chimps *M- major - - - -9 subtypes/clades - - - -circulating recombinant forms - - -**Clade B most common (US +) N,O- W. Africa P- similar to SIV |
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collection of Data
for new incidence reports |
BED capture enzyme immunossay
checks ratio of anti-HIV IgG vs total IgG Anti-HIV increases over time - so reflects time of infection |
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HIV
transmission |
3 modes
- sexual contact - blood . - perinatal . ***Viral load is main predictor (NO transmission, when viral load <1500) |
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STIs affect on HIV
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STIs increase risk of HIV transmission
- - - especially Herpes Simplex - - - (acyclovir-- NO decrease) |
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Treatment of HIV
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HAART
(highy active antiretroviral therapy) at least 3 active agents RTIs (reverse transcriptase inhibitors) protease inhibitors fusion inhibitors integrase inhibitors CCR5 inhibitors |
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HIV
Therapeutic success |
***undetectable viral load within 6 months
prevent accumulation of mutations resulting in full resistance |
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AIDS
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CD4<200 (once)
or one of the listed conditions |
