comparing a lternative vaccination schedules to control prrs
DESCRIPTION
Recent information about alternative vaccination schedules to control (first step before eradication) PRRS in pig farm. Comparing a lternative vaccination schedules to control PRRS I. Díaz , M. Gimeno , A. Callén , J. Pujols , S. López , C. Charreyre , F. Joisel , E. Mateu - PowerPoint PPT PresentationTRANSCRIPT
Recent information about alternative vaccination schedules to control (first step before eradication) PRRS in pig farm
Comparing alternative vaccination schedules to control PRRS
I. Díaz, M. Gimeno, A. Callén, J. Pujols, S. López, C. Charreyre, F. Joisel, E. Mateu & T. Jirásek([email protected])
EXPERIMENT 1: Development of PRRSV-specific immune responses after repeated PROGRESSIS®
immunizations
IV IV IV
MLVIV IV
MLV
EXPERIMENT 2: Development of PRRSV-specific immune responses after attenuated vaccine (MLV) primo-immunization followed with a MLV or PROGRESSIS® recall vaccination
IV = Progressis®Ch= Challenge. Strain2749, EU type. ORF5 99% similar to LV
Evaluation of the humoral responses:
• PRRSV-specific total antibodies (ELISA IDEXX)• PRRSV-specific neutralizing antibodies (VNT)
Evaluation of the cell-mediated immune response:
• PRRSV-specific IFN-γ-secreting cells (IFN-γ-SC)
(n=21) Months of age
GROUP 1,5 2,5 3,5 4,5 5,5 6,5 7.5 (+0) +21
A - IV IV - - IV CH END
B IV IV - - IV IV CH END
C - - - - - - CH END
Experiment 1. Development of PRRSV-specific immune responses after repeated
PROGRESSIS® immunizations
TOTAL ANTIBODIES (ELISA Idexx)
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
-7 PI 0 PI +7 PI +14 PI + 21 PI
S/P
ratio
A B C
Months of age
Group 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
A IV IV IV Ch END
B IV IV IV IV Ch END
C Pl Pl Pl Ch END
Positive pigs
Day +0 Day +7
Group A 5/7 7/7
Group B 4/7 5/7
Group C 0/7 0/7
Challenge
Months of age
Group 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
A IV IV IV Ch END
B IV IV IV IV Ch END
C Pl Pl Pl Ch END
Months of age7.5 (0 dpi) 14 dpi 21 dpi
A1/71
7/7a
3.7 ± 0.57/7
4 ± 0.6a
B3/7
2.3 ± 0.67/7a
3.8 ± 1.57/7
4.6 ± 0.8a
C0/7
-2/7b
4 ± 06/7
3 ± 0.9b
NEUTRALIZING ANTIBODIES (VNT)
PROPORTION OF POSITIVE PIGSMEAN TITRES (log2) ± STAND. DEV.
∅
PRRSV
∅
PRRSV
ELISPOT IFN-γ
CELL-MEDIATED IMMUNITY (ELISPOT IFNγ)
PRR
SV-s
peci
fic IF
N-γ
-SC
/ 10
6 PB
MC
Challenge1.5 2.5 3.5 4.5 5.5 6.5 7.5 (+0
PI)+7 PI +14 PI +21 PI
0
25
50
75
100
125
150
175
A B C
a
b
a
a
a
b
a
b
c
a†
b
a‡
Months of age
Group 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
A IV IV IV Ch END
B IV IV IV IV Ch END
C Pl Pl Pl Ch END
Development of PRRSV-specific immune responses after repeated PROGRESSIS®
immunizations
IV IV IV
1. Repeated IV immunizations increased cell-mediated immunity and neutralizing antibodies –after the second immunization-.
2. Development of cell-mediated immunity are supposed to be T helper cells and cytotoxic T-cells (Piras et al., 2005). The pattern observed in the present study agreed with the development of memory cells.
3. After the challenge, IV vaccinated pigs showed a significant increase in the neutralizing antibodies production –in proportion of positive pigs and in mean titres-.
VACCINATION SCHEDULE BALANCE SAFETY/EFICACY
(n=32) Months of age
GROUP 1,5 4,5 5,5 6,5 7,5
A MLV IV - CH END
B MLV MLV - CH END
C MLV IV IV CH END
D - - - CH END
EXPERIMENT 2: Development of PRRSV-specific immune responses after attenuated vaccine
(MLV) primo-immunization followed with a MLV or PROGRESSIS® recall vaccination
IV = Progressis®Ch= Challenge. Strain2749, EU type. ORF5 99% similar to LV
Evaluation of the humoral responses:• PRRSV-specific total antibodies (ELISA IDEXX)• PRRSV-specific neutralizing antibodies (VNT)
Evaluation of the cell-mediated immune response:• PRRSV-specific IFN-γ-secreting cells (IFN-γ-SC)
Virological analysis• Viremia by RT-PCR (+0,+3,+7,+14,+21)
(n=32) Months of age
GROUP 1,5 4,5 5,5 6,5 7,5
A MLV IV - CH ENDB MLV MLV - CH ENDC MLV IV IV CH ENDD - - - CH END
0
0,4
0,8
1,2
1,6
2
2,4
2,8
3,2
1,5 2,5 3,5 4,5 5,5 6,5 END
S/P
ratio
ABCD
Challenge
TOTAL ANTIBODIES (ELISA Idexx)
Months of age4,5 5,5 6,5 (0 dpi) 14 dpi
AMLV+IV
1/81 ± 0
2/8ab
2 ± 1.45/8a
2.8 ± 0.88/8a
3.2 ± 0.7ab
BMLV+MLV
0/8-
4/8a
1.5 ± 15/8a
1.6 ± 0.97/8ab
2.1 ± 1.3b
CMLV+IV+IV
3/81 ± 0
5/8a
1.4 ± 0.5 6/8a
2.2 ± 1.68/8a
3.6 ± 1.2a*
DCONTROL
0/8-
0/8b
-0/8b
-4/8b
2.2 ± 0.5b
PROPORTION OF POSITIVE PIGSMEAN TITRES (log2) ± STAND. DEV
(n=32) Months of age
GROUP 1,5 4,5 5,5 6,5 7,5
A MLV IV - CH END
B MLV MLV - CH END
C MLV IV IV CH END
D - - - CH END
NEUTRALIZING ANTIBODIES (VNT)
(n=32) Months of age
GROUP 1,5 4,5 5,5 6,5 7,5A MLV IV - CH ENDB MLV MLV - CH ENDC MLV IV IV CH ENDD - - - CH END
1,5 2,5 3,5 4,5 5,5 6,5 (+0 PI) +7 PI +14 PI +21 PI0
25
50
75
100
125
150
175
200
A B C
PRR
SV-s
peci
fic IF
N-γ
-SC
/ 10
6 PB
MC
a
a
b
c
a
ab
b
c
a†
b
ab†
b
a
ab
b
aa
b
b
b
MLVPrimo-immunization
Re-vaccination
Challenge
CELL-MEDIATED IMMUNITY (ELISPOT IFNγ)
(n=32) Months of age
GROUP 1,5 4,5 5,5 6,5 7,5
A MLV IV - CH END
B MLV MLV - CH END
C MLV IV IV CH END
D - - - CH END
A 0 3 79 - - +12 - - -15 - - +18 - - -21 - - -24 - + -27 - - -30 - - -
VIREMIA by RT-PCR
B 0 3 7 10 - - -13 - - -16 - - +19 - - -22 - - -25 - - -28 - - -31 - - -
C 0 3 7 11 - - -14 - - -17 - - -20 - - -23 - + -26 - + -29 - - -32 - - -
D 0 3 7 1 - + -2 - + -3 - + -4 - + -5 - + -6 - + +7 - + -8 - + -
No significant differences among
vaccinated groups
Development of PRRSV-specific immune responses after attenuated
vaccine (MLV) primo-immunization followed with a MLV or
PROGRESSIS® recall vaccination
After a MLV primo-immunization:
1. IV re-vaccination induced a significant increase in the development of cell-mediated immunity (anamnestic response).
2. After the challenge, MLV+IV+IV group developed the highest PRRSV-specific immune responses (cell-mediated immunity and neutralizing antibodies).
3. All the vaccination schedules reached similar levels of protection.
MLV
IV IV
MLV
VACCINATION SCHEDULE BALANCE SAFETY/EFICACY
