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31 Cards in this Set
- Front
- Back
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Retroviridae Properties
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Enveloped, spherical
(+) ssRNA "diploid" reverse transcriptase A,B,C,D type particles Simple and Complex viruses |
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Simple Retroviral Genomes
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GAG: group antigen gene (capsid)
POL: polymerase (reverse transcriptase) ENV: envelope glycoprotein gene LTR: long terminal repeat (promotor) |
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Complex (HIV) retroviral genome
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additional proteins on top of simple retroviruses
used for activation, regulation, and infection of virus |
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HIV life cycle: attachment/penetration
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HIV attaches to CD4 cell
VAP is gp120-gp41 viral RNA carried to nucleus |
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HIV life cycle: Replication
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reverse transcriptase makes DNA copy of viral genome, integrating it into host cell genome
LTR is promotor, produces mRNA which is exported from nucleus |
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HIV life cycle: Assembly and release
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RNA forms w/ viral proteins to form RNP capsid
it associates w/ matrix protein and buds through plasma membrane |
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Simple Retrovirus Gene Expression
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3 main structural genes (gag, pol, env)
LTR initiates transcription into mRNA protease cleaves mRNA into mature proteins |
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Complex Retrovirus Gene Expression
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LTR begins transcription, splicing of regulatory proteins occurs
proteins are made and then aid in virus processing and exit |
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AIDS Infection
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HIV stage 3: confirmed HIV, CD4+ <200 / CD4+ % of total lymphocytes <14
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Lenitiviruses
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slow viruses in Retroviridae
cause immune difficiency, hematopoietic and CNS disorders HIV-1 and HIV-2 |
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Origin of HIV
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virus strain ZR59 isolated in Kinshasa, Congo 1959
came from Buntu male monkey |
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HIV pathogenesis
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tropism for CD4 expressing T-cells
uses CCR5 and CXCR4 co-receptors can be passed through sexual intercourse, anal and vaginal |
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Course of Infection: Acute
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virus production
lymphadenopathy and flu-like symptoms virus and Ag detectable in blood CMI reduces viremia |
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Course of Infection: Asymptomatic
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3-4 weeks post infection, can last years
latency, viremia decreases increased viral load=closer to AIDS |
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Course of Infection: Development of AIDS
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when CD4+ cell drop below 500 cell/ul
headache, weight loss, increased infections increase in viremia and decrease in CD8+ |
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Course of Infection: Late Stage
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increase in virulence properties, expands to new cells
rapid replication, enhanced neurotropism |
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Host response to HIV
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10% have AIDS in 2-3 years
80% have AIDS in 10 years 10-17% have AIDS in no less than 20 years replication occurs best in activated T-cells |
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Immune System Response: CD4+ cell dysfunction
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causes decreased IL-2 production, reduced overall IR
can also cause inappropriate IR |
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Immune System Response: CD8+ cell dysfunction
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abnormally high following infection, to make up for less CD4+
later, a decrease in CD8+ because no cytokines are released to trigger them |
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Immune System Response: monocyte/macrophage cell dysfunction
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defects in chemotaxis, inability to proliferate T-cells, Fc-receptor fxn
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Immune System Response: NK cell dysfunction
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depend on IL-2, if no cytokine then no NK cell IR
leaves body susceptible to other infections |
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Humoral IR
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Ab against HIV are made early, can neutralize virus early
ineffective against later viral isolates |
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Cellular IR
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CD8+ cytotoxic lymphocytes against HIV slow disease progression, but a rapid drop in CD8+ activity occurs during end stage
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AIDS associated Illnesses
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Kaposi's Sarcoma: cancer from HHV-8
B-cell Lymphoma: 100X more common in HIV patients than normal, HHV-8 and EBV common factor |
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HIV Lab Diagnosis
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EIA or ELISA
Western Blot PCR |
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HIV Treatment: Attachment Inhibitors
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Neutralizing Ab: against gp40/gp120
Pfizer: binds to CCR5 |
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HIV Treatment: Fusion Inhibitors
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Fuzeon: binds to glycoprotein 120 in HIV surface
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HIV Treatment: Nucleoside Reverse Transcriptase Inhibitors
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Lamivudine, Tenofovir, Zidovudine
reverse transcriptase incorporates these analogs into DNA, causing disruption of replication |
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HIV Treatment: Integrase Inhibitor
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Efavirenze
prevents integration of viral cDNA into host cell genome |
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HIV Treatment: Protease Inhibitors
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drugs block proteolytic processing of viral sub-units, disrupting production
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HIV Treatment: Circumcision
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possible 50% reduction in acquiring HIV
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