Opened 13 years ago

Closed 13 years ago

#7 closed enhancement (fixed)

Add PFU (Plaque forming units)

Reported by: Gunther Schadow Owned by:
Priority: critical Milestone:
Component: Keywords:
Cc:

Description (last modified by Gunther Schadow)

Plaque forming units, an entitic number, like CFU. This is not quite an arbitrary unit.

WHO EXPERT COMMITTEE ON BIOLOGICAL STANDARDIZATION (55th Edition) WHO Technical Report #932; copyright 2005 ....

  1. Virus titration for infectivity

Each working seed lot should be assayed for infectivity in a sensitive assay in cell cultures.

  • A plaque assay may be used in Vero or other sensitive cells. Titre should be determined by counting the number of visible plaques developed, and results recorded as PFU/ml.
  • An immunofocus assay may also be used to measure virus titre. The assay is based on the visualization of infected areas of a cell monolayer by probing with dengue serotype-specific monoclonal antibodies. Results should be recorded as FFU/ml.
  • A tissue culture infectious dose assay may also be used to determine virus titre. Results should be recorded as CCID50/ml.

If international reference standards become available, immunizing doses should be expressed as relative potencies rather than CCID50 because experience shows that this reduces variability between assays.

Change History (3)

comment:1 Changed 13 years ago by Gunther Schadow

Description: modified (diff)
Type: defectenhancement

More explanation:

Viral infectivity in a sensitive assay in cell culture where the titer is determined by counting the number of visible plaques developed following viral infection of a sensitive cell culture and results recorded as PFU/ml.

comment:2 Changed 13 years ago by Gunther Schadow

Description: modified (diff)

comment:3 Changed 13 years ago by Gunther Schadow

Resolution: fixed
Status: newclosed
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