Virus-cell interactions (CPEs) Flashcards Preview

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Flashcards in Virus-cell interactions (CPEs) Deck (19)
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1
Q

CPEs

A

Alterations in the morphology of cells due to virus infection

  • Usually degenerative processes
  • Mainly observed in cell cultures
  • Direct damage of viruses on cells
2
Q

Give examples of direct damage of viruses on cells

A
  • Toxic effect of adsorption
  • Virus proteins inhibit translation
  • Cytoplasmic damage
  • Cytoskeleton depolymerisation
  • Expression of fusion proteins
3
Q

Light microscopy of CPEs

A
  • Some cells don’t need staining
  • Staining gives more detail
4
Q

Tools for the detection of virus multiplications in vitro

A
5
Q

Why is it that not all virus infections result in CPEs?

A
  • The cytopathic character of a virus may change due to mutation
  • The CPE in question isn’t always found with the virus
6
Q

The appearance of the CPE is influenced by…

A

The multiplicity of infections (MOI)

  • The most characteristic CPE is seen by a low MOI
7
Q

The host cell can cause a difference in the…

A

CPEs expressed in the cell

8
Q

List the types of CPE

A
  • Inclusion body
  • Cell Rounding
  • Syncytium-formation
  • Lumpy cell nucleus
  • Cell vacuolisation
  • Hemadsorption
  • Plaques
9
Q

Inclusion bodies (General)

A
  • Can be Intranuclear or intracytoplasmic
  • Found at the site of nucleocapsid assembly → virus deposition
  • Seen in stained cells
    • Surrounded by a halo
10
Q

Intranuclear inclusion bodies

A
  • Caused by DNA/RNA virus replicating in the nucleus
  • Cowdry-A/Cowdry-B types depend on state of synthesis of macromolecules
  • Basophyl, amphophyl, eosinophyl
11
Q

Intracytoplasmic inclusion bodies

A
  • Usually caused by RNA viruses
  • DNA viruses replicating in the cytoplasm
  • Eosinophyl, rarely basophyl
  • Pathognomic: Negri bodies, Guarnieri bodies
12
Q

Cell Rounding

A
  • One of the most common CPEs
  • Cytoskeleton depolymerisation
  • Loss of electrolytes
13
Q

Syncytium-formation

A
  • Caused by enveloped viruses only
  • Fusion proteins on the surface of the virus
    • Used for viral penetration
  • Giant cells with many nuclei
    • Polykaryocytes
    • Syncitia
14
Q

Lumpy cell nucleus

A
  • Chromatin conglomeration, rearrangement
  • Changed refraction (parvo)
  • Nucleus lumpy disintegration
15
Q

Cell vacuolisation

A
  • Vacuoles formed in the cells
    • In the nucleus or
    • In the cytoplasm
16
Q

Hemadsorption

A
  • Viral hemagglutinin is expressed on the surface of infected cells
  • RBCs added into the culturing medium, then washed away 30 mins later
  • Infected cells capture RBCs
  • Diagnosis of:
    • Paramyxoviruses
17
Q

Plaques

A

Local/focal

  • Certain viruses are more frequent in plaques
  • Lower MOI = more freqeuntly plaques are formed
  • Syncytia are seen as plaques
18
Q

Advantages of plaques

A
  • Virus purification: Subsequent passages of viruses taken from singular plaques - establishment of virus strains
  • Virus quantification: Plaque counting
19
Q

Non-specific CPEs: differentiation

A
  • Compare with uninfected control
  • Passage the isolate
  • Perform direct demonstration