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42 Cards in this Set
- Front
- Back
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Steps in Viral replication
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attachment
entry & uncoating replication assembly release |
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attachment of HIV
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binds CD4 & co-receptor of T cell
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attachment of EBV
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binds CD3 (complement) receptor on B cell
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attachment of Rabies
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binds ACh R on neuron
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attachment of Influenza A
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binds sialic acid on epithelial cells
hemagluttination |
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Attachement of viruses
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random, electrostatic, viral ligand/host R, independent of temp
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Entry & Uncoating of Virus
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entire virus or nucleocapsid into cytoplasm, then remove capsid
RM endocytosis (both) Direct penetration (naked) Fusion (enveloped) |
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receptor mediated endocytosis
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for either enveloped or naked
requires low pH to releas from vesicle |
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direct penetration
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entry for non-enveloped virus (no vesicle)
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fusion
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entry for enveloped virus (no vesicle)
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Methylisoxazole
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interferes with uncoating of Picornavirus
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Amantidine
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(& Rimantidine)
interfere with uncoating of influenza |
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Tromantadine
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inhibits penetration of herpes
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Enfuvirtide
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inhibits fusion of HIV w/CD4
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Viral Replication DNA viruses
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Early- virion DNA
Late- Progeny Translation depends on capping, splice sites, polyadenylation End Problem |
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Early replication
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part of DNA virus replication
make proteins needed to subvert host machinery requires DNA dependent RNA polymerase |
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Late replication
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part of DNA virus replication
make progeny requires DNA polymerase ss virus must synthesize a ds intermediate |
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End Problem
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in DNA virus replication
Polyoma & Papilloma are circular- no problem Adeno- linear, synthesizes primer proteins HBV uses reverse transcriptase |
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RNA dependent RNA polymerase
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carried by all RNA viruses
for replication (retrovius carries RNA dependent DNA polymerase) |
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replication of ss +RNA virus
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ss +RNA reads like mRNA
may make ds intermediate DNA intermediate can integrate into host |
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replication of ss -RNA virus
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RNA dependent RNA polymerase to synthesize mRNA from - strand
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replication of segmented ss -RNA virus
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happens in NUCLEUS
Cap snatching to initiate mRNA synthesis |
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Cap Snatching
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segmented ss -RNA virus uses to initiate mRNA synthesis
Capped RNA primers are cleaved from cellular nuclear RNA |
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replication of ds RNA
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synthesize + strand from - strand of parent
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replication of retrovirus
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use - strand DNA intermediate to make + strand RNA progeny
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Quasi species
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found in RNA virus
advantage over host b/c always changing high mutation rate |
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rare direct viral damage
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fever, HA, rash
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Shutoff
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Poliovirus
Shuts off host cell machinery cell dies after virus leaves virus cleaves complex responsible for cap dependent translation |
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outcome of non-HIV retro viral infection
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persistant infection
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outcome of HIV, Hep B & C infection
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chronic infection
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latent infection caused by
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lambda virus in E coli
beta virus in diphtheria HSV |
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cellular changes due to viral infection
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Inclusion bodies- Herpes
Syncytia- Measles Transformation- leads to tumor Apoptosis & Cellular Degeneration |
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Ebola Virus Toxin
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Glycoprotein
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Adenovirus Toxin
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penton
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Rotavirus toxin
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NSP4
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Viral Toxins
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Ebola- glycoprotein
Adeno- penton Rota- NSP4 |
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Viral Escape Mechanisms
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IFN activates genes in some virus
Escape N ABs & CTLs |
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ACE-2
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receptor for SARS
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delta ORF
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virulent SARS
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SARS
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coronaviridae
ACE-2 is R delta ORF was mutation never efficient enough to switch to human host reservoir is bat |
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Influenza
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8 segments in genome
surface GPs (HA & NA) HA is fusion prot NA cleaves sialic acid protein N1 inhibits IFN activation |
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Vector Borne Illnesses
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from Flavivirus
Grippe-like (Dengue) Fever- fever, bone pain, loss ap DHF/DSS- shock, cap leak West Nile, SLE: flu, enceph Yellow Fever: hem fever, cap leak, hepatitis |
