OS18 - Open Session 2018 Borgo Egnazia (Puglia), Italy 29 - 31 /10/2018 EuFMD Sessions\Open Session\Archive-2018\Open 2018 - Italy\6. Online & Streaming\PPTs

1. OS18
Potency assessment of FMD vaccine
using standardized serological assays
Syed M. Jamal
Department of Biotechnology
University of Malakand
Pakistan

2. OS18
Potency test for FMD vaccine
• Limitations of Potency test:
Varying outcome
Disease security hazards
Costly
One valency in any given trial
Animal welfare
• European Pharmacopoeia
Challenge protection studies in cattle
Determination of PD50

3. OS18
Serological based methods
Alternatives to challenge-protection test provided that a
correlation is established between antibody titre and protection
Advantages:
1. No logistic problems
2. No disease security hazards
3. Relatively in-expensive
4. More than one valency at given time
5. Simultaneous testing of several vaccines

4. OS18
• Mackowiak et al., 1962
• van Bekkum, 1970
• Sutmoller and Vieira, 1980
• Pay and Hingley, 1987
• van Maanen and Terpstra, 1989
• Amadori et al., 1991
• Pay and Hingley, 1992a,b
• Dus Santos et al., 2000
• Barnett et al., 2003
Studies on correlation between antibody titre and
protection

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• Correlation between antibody titre and level of protection
accepted worldwide
• Test results often vary considerably between laboratories
• difference between route and dose of challenge virus
• the condition of cattle
• the interval between vaccination and challenge
• the type of serological test
• sensitivity of cells used in neutralization test

6. OS18
Objectives
Standardization of antibody titres against O/Manisa
for determination of vaccine potency using:
• A standardized commercial PrioCHECK FMDV type O
ELISA
• Inclusion of a standard 4 week post-vaccination serum
from a cow vaccinated with O/Manisa FMD vaccine in
both the ELISA and VNT

7. OS18
 Serum samples from 18 potency tests performed at:
• Belgium (n=10)
• The Netherlands (n=6)
• The United Kingdom (n=2)
 Standard control serum (4 week post-vaccination serum from
O/Manisa vaccinated cow)
 Serum samples were tested in respective laboratories
using:
• Neutralization test
• ELISA (PrioCHECK)
 Unit/standardized antibody titres determined by
subtracting the log titre of a standard control serum from that of
the test serum
 Results were analysed using logistic regression
Materials and Methods

8. OS18
RESULTS: Antibody titres v/s protection
---------- Pirbright
---------- Ukkal
Lelystad
• Significant difference in antibody
titres among laboratories
• The slope of the curve steeper in
VNT compared to ELISA
---------- Pirbright
---------- Ukkal
Lelystad

9. OS18
Standardized/Units antibody titres v/s protection
---------- Pirbright
---------- Ukkal
Lelystad
Unit antibody titres reduced variation
among laboratories
BUT
Significant difference still present
---------- Pirbright
---------- Ukkal
Lelystad

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Conclusions
Inclusion of the standard serum reduced variation between
the laboratories.
However, significant differences were still present, which could be
due to differences in vaccine composition.
Inclusion of a standard serum is a good way to make results
between laboratories more comparable.
 Cattle vaccinated with 1/3rd dose of a standard FMD vaccine
(containing 3 PD50) should have antibody titre at least as high as that
of a standard serum representing 50% protection.

11. OS18
Acknowledgements
• CVI-lelystad, the Netherlands
• CODA-CERVA, Belgium
• Pirbright Institute, United Kingdom
• Thanks to the EuFMD for supporting my participation in the OS18

12. OS18