Download Intra-serotype chimeric FMD Vaccine Antigen elicit protection in cattle, F.Maree

Appendix 20
Introduction
• Effective control of FMD:
Intra-serotype chimeric FMD vaccine
antigen elicit protection in cattle
- Physical barriers, including fencing
- Immune barrier using vaccination
Vaccination
F.F. Maree
Transboundary Animal Diseases
Physical barriers, like fences
Introduction
A key statement from discussions with DAFF
• The control of FMD by vaccination is complicated by:
regarding what is needed in the control of FMD:
- Multiple genetic lineages (and antigenic variants) in different
geographical regions.
- Adaptations of field strains are cumbersome.
“We need better vaccines and
- Stability of the virus and/or antigen.
better fences”
- Longevity of antibody responses elicited by vaccines.
- Developing countries: lack of vaccines tailored to their conditions
SAT2 Antigenic variation
SAT2 antigenic variation
1.2
Vaccine match based on r-values
ZIM/07/83/2
KNP/19/89/2
1
ERI 12/89/2
RWA/02/01/2
0.8
0.6
Ref sera:
r-value criteria
ZIM/7/83
0.4
KNP/19/89
0.2
RWA/2/01
0
ERI/12/89
0
20
40
60
80
100
120
r-Values of SAT-2 virus isolates from different topotypes compared to antiserum prepared to the reference strains
KNP19/89 (I), ZIM7/83 (II), RWA/2/01 (VIII) and ERI/12/89 (X).
SAT2 vaccine
strains
SAT2 reference
viruses
Open Session of the EuFMD: 2012, Jerez de la Frontera, Spain
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Appendix 20
A joint approach between conventional, inactivated
vaccine technology and genetic engineering
Rational design of vaccines
• Vaccine containing a inter-serotype chimeric antigen elicited immune
responses similar to that of the parental antigen.
FMDV capsid
• Functional amino acid residues involved in cell culture adaptation of
SAT vaccine strains have been identified and introduced in field viruses
using reverse genetics.
• Genetically engineered SAT2
and SAT3 viruses revealed diverse
stabilities to mild acidic conditions - stability of the capsid can be
engineered.
V
• Yield of chimeric vaccine antigen and growth of viruses can potentially
be improved by modification and improvement of enzymatic functions.
Chimera capsid
• Epitope switching may be used to modify antigenicity of an infectious
copy virus.
Construction of infectious chimeric particles
SAT2/ZIM/07/83
vSAT2
Vaccination of cattle with a SAT2/SAT2 vaccine
r-values for SAT2 viruses
1.20
ZIM/07/83/2
1.00
KNP/19/89/2
D0
ERI 12/89/2
D7
D14
D21
D32
0.80
SAT2/ZIM/17/91
vZIM17/SAT
SAT2/ZIM/14/90
vZIM14/SAT
chimera
0.60
0.40
0.20
0.00
KNP/19/89/2
ZIM/07/83/2
ZIM/17/91/2
ZIM/14/90/2
vZIM17/SAT2
vZIM14/SAT2
Vaccinate
2ml containing
8 μg 146S:
Challenge:
ZIM/14/90
- ZIM/14/90
- Chimera
- Placebo
Neutralising antibody titers
Vaccination of cattle with a SAT2/SAT2 vaccine
Chimeric vaccine
Parental vaccine
3.0
Chimeric vaccine
Cattle vaccinated with chimera
3.0
2.5
2.5
2.0
2.0
1.5
Parental vaccine
Cattle vaccinated with parental
3.00
3.00
2.50
2.50
2.00
2.00
1.5
1.50
1.0
1.50
1.0
1.00
0.5
0.5
0.0
0.0
Day 0
Day 7
Day 14
Day 21
1.00
0.50
0.50
0.00
Day 0
Day 7
Day 14
Day 21
Day 0
Day 7
Day 14
Days post-vaccination
•Cattle vaccinated with 8 ug of antigen
•Challenge with 104 ID50 FMDV at 21 dpv
•Sera tested with a SAT2 solid-phase competition ELISA (SPCE)
Day 21
0.00
Day0
Day7
Day14
Day21
Days post-vaccination
•Cattle vaccinated with 8 ug of antigen
•Challenge with 104 ID50 FMDV at 21 dpv
•Sera tested with a SAT2 solid-phase competition ELISA (SPCE)
Open Session of the EuFMD: 2012, Jerez de la Frontera, Spain
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Appendix 20
Neutralisation titers compared to protection
Vaccine
Animal
number
SAT2/ZIM/14/90
vZIM14/SAT
Neutralisation titers compared to protection
Temperature
(ºC)
Neutralisation
titer
Lesions postchallenge
P-1
P-2
39.5
39.3
2.06
2.38
None
None
P-3
P-4
40.1
39.6
2.02
2.47
Mild
None
3
P-5
P-6
P-7
40.0
38.6
39.7
2.15
2.38
2.00
Mild
None
None
2,5
C-1
C-2
39.6
39.7
2.43
2.82
None
None
1,5
C-3
C-4
40.3
39.1
2.04
2.26
None
None
1
C-5
C-6
C-7
38.7
39.6
39.2
2.59
2.40
2.61
None
None
None
0,5
1
2
39.6
38.9
<1.3
<1.3
Severe
Severe
VNT titers
2
0
Control
Protected
parental
Unprotected
parental
Structurally modified master seed viruses to
enhance conventional foot-and-mouth disease
virus vaccine production
Antigenic relatedness to SAT2 viruses
r1= heterologous titer
homologous titer
1,20
Protected
chimera
1,00
0,80
good
vaccine
match
0,60
0,40
poor
vaccine
match
0,20
0,00
SAR/3/04
KNP/19/89
antiserum vZIM14-SAT2
antiserum SAT2/ZIM/7/83
ZIM/14/90
viruses
ZIM/7/83
antiserum SAT2/ZIM/14/90
antiserum SAT2/KNP/19/89
antiserum SAT2/SAR/3/04
Wellcome Trust translational award
Interpentamer residues aimed at stabilising the
capsid
Global FMD Research Alliance
Consortium consisting of:
Institute for Animal Health, Pirbright
Structural model of SAT2
pentamer
Transboundary Animal Diseases, ARC-OVI
Plum Island Animal Disease Centre, USDA
University of Oxford
Side view of the pentamer,
showing the interpentamer
interface
MSD Animal Health
Open Session of the EuFMD: 2012, Jerez de la Frontera, Spain
3
Appendix 20
In vitro measurement of capsid stability
Neutralising Ab response in guinea pigs
Thermofluor assay
A24
vSAT2
Mut B
VNT titers of vSAT2 (wild-type) and mutant vaccinated GPs
---
A24
(55 °C)
---
Mutant B
(53 °C)
---
Mutant H
(52 °C)
3
---
Mutant F
(51 °C)
2.5
---
Mutant A
(51 °C)
---
vSAT2 WT
(47 °C)
---
Mutant C
(45 °C)
3.5
2
1.5
1
Shift of 6 °C
11.3 % increase in dissociation temperature using
Thermofluor assay of mutant B.
0.5
0
vSAT2, 1 month
Conclusion
•
Intra-serotype Chimeric Vaccine VZIM/14-SAT2 elicited a protective
immune response in cattle comparable to that of the conventional
vaccine; SAT2/ZIM/14/90.
•
Similar antigenic profiles observed for both the chimera and
conventional vaccines.
•
Thermo-stable SAT2 capsids were designed based on structure and
infectious viruses based on a capsid stabilised mutation indeed
shows an increase >10% in dissociation temperature
vSAT2, 6 months
Mutant, 1 month
Mutant, 6 months
Acknowledgements
P. Nsamba;
K. Scott;
B. Blignaut;
P. Mutowemba;
Makarere University, Uganda
TADP, ARC-OVI
TADP, ARC-OVI
TADP, ARC-OVI
A. Kotecha, E. Fry, D. Stuart
B. Charleston
E. Rieder
D. Goovaerts, P .Guntram
Oxford Structural biology group
IAH, Pirbright
PIADC, USDA
MSD Animal Health
Open Session of the EuFMD: 2012, Jerez de la Frontera, Spain
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