TABLE 8.2

Listing of analytical methods applied to qualify and quantify viral preparations

Method

Duration

Principle

Necessitate

labeling

Analytical

Range related

to total

particle count

Reproducibility

% CV

REF

Infectivity

assay

Plaque assays

days

Cytopathic effect

no

>10°

7%

[ 8]

Tissue culture infectious doses

(TCID50)

Cytopathic effect

no

>10°

27%

[ 8]

Fluorescence focusing assay (FFA)

Fluorescent marker detection

yes

>10°

N.D.

[ 9]

Activity assay

Hemagglutination assay

hours

Hemagglutination i.e.,

attachment to syalic acid

residues of Red blood cells

no

>10 6

30–40%

[ 10]

Immuno-based

assays

Single Radial Immunodiffusion (SRID)

assay

days

Specific Immunoprecipitation

for viral antigens in a gel

no

N.A.

N.A.

[ 11]

ELISA

hours-days Capture of viral antigens by

specific antibodies

yes

N.A.

N.A.

[ 12]

Genome

quantification

Quantitative PCR (qPCR and

RT-qPCR)

hours

Viral DNA or RNA

amplification

yes

>10°

45–130%

[ 13]

ddPCR and dd RTPCR

hours

yes

>10°

N.A.

[ 7]

Total particles

counting

Individual

particle

counting

Negative Stain

Transmission Electron

Microscopy (NSTEM)

days

Visual counting

no

N.D.

N.D.

[ 4]

Atomic Force

Microscopy (AFM)

(Continued)

Analytics and virus production processes

211