Virology 2 Flashcards
Name of whole virus particle?
Virion
What is the process of viral life?
Attachment Penetration Uncoating Transcription & translation of viral proteins Genome replication Assembly Maturation Release
What is the name of the receptor used by flu virus?
Sialic acid, which is a component of plasma membrane gangliosides
Three types of penetration; they are? Most common?
Viral translocation - not much known about, only naked.
Surface fusion (from without) - enveloped viruses only; pH independent
Receptor mediated endocytosis - naked or enveloped, MOST COMMON, pH dependent
How does release of naked viruses differ from that of enveloped… any exceptions?
Naked happens just because the cell bursts. The naked virus assembles, and during replicaiton of the genome the cell isn’t functioning well, and eventually it lyses.
Enveloped viruses assemble associated to a membrane, and the glycoprotein spikes attach to the membrane and the bud forms there. The plasma membrane then invaginates and the virus buds with its new enveloped made from the host cell plasma membrane.
Exception: some enveloped viruses exit naked because they form a vesicle by budding on intracellular machinery membranes instead of external plasma membranes, and then the vesicle fuses with the external plasma membrane and the virus exits uncoated.
Which viruses are spread by insects?
Yellow fever
Malaria
Dengue
Most common route of viral ifnection?
Resp tract
What are the immune defecnces of the RT?
Secretory IgA Alveolar macrophages Tonsillar lymphoid tissue Ciliary escalator Mucus
M cells, where are they and waht’s their significance?
Scattered among peyer’s patches and lymphoid aggregates
Antigen uptake and presentation to initiate immune response
Used by pathogens for entry e.g. coronavirus, HIV
How does flu attach?
Haemagluttinin
How does flu detach?
Neuraminidase
What is the genome of flu?
ssRNA(-)
How does rabies disseminate?
Nerves
Very long incubation period w/ years before sx?
Insidious
Infection with no symptoms but may be transmitted?
Subclinical (carrier state)
Persists beyond acute onset and may be reactivated
Latent
Infectious agents persist with symptosm and slow to resovlve
Chronic
Rapid onset, short lived
Acute
What is cell rounding?
Cytopathic effect of virus
What are the cytopathic effects?
Cell rounding Formation of inclusion bodies Syncitia formation Cell fusion Inhibition of protein synthesis Inhibition of DNA/mRNA synthesis and degradation
Then transformation or cell death
Damage to cells by viruses can be…
direct e.g. cell death
indirect e.g. immunosuppression
Which chemical is produced in abundance in virally infected tissue and why do we care?
NO
It’s produced during inflammation from L-argnine by iNOS, and inhibits viral replication.
Its damaging to the tissue at high concentrations
What are free radicals?
Superoxide (O2-) and nitric oxide (.NO)
Why does measles virus cause immunosuppresion?
Infects DCs and macrophages causing their destruction
