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Comparing a lternative vaccination schedules to control PRRS

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

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Comparing a lternative vaccination schedules to control PRRS

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  1. Recent information about alternative vaccination schedules to control (first step before eradication) PRRS in pig farm

  2. 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 (tomas.jirasek@mevet.cz)

  3. EXPERIMENT 1: Development of PRRSV-specificimmune responses afterrepeated PROGRESSIS®immunizations IV IV IV IV IV MLV MLV • EXPERIMENT 2: Development of PRRSV-specificimmune responses afterattenuatedvaccine (MLV) primo-immunizationfollowedwith a MLV orPROGRESSIS® recallvaccination

  4. Experiment 1. Development of PRRSV-specificimmune responses afterrepeated PROGRESSIS®immunizations 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)

  5. TOTAL ANTIBODIES (ELISA Idexx) Challenge

  6. NEUTRALIZING ANTIBODIES (VNT) PROPORTION OF POSITIVE PIGS MEAN TITRES (log2) ± STAND. DEV.

  7. ELISPOT IFN-γ ∅ ∅ PRRSV PRRSV

  8. CELL-MEDIATED IMMUNITY (ELISPOT IFNγ) a a‡ a PRRSV-specific IFN-γ-SC / 106 PBMC a a† a b a b b b c Challenge

  9. Development of PRRSV-specificimmune responses afterrepeated PROGRESSIS®immunizations IV IV IV Repeated IV immunizationsincreasedcell-mediatedimmunity and neutralizingantibodies –afterthesecondimmunization-. Development of cell-mediatedimmunity are supposedtobe T helpercells and cytotoxic T-cells (Piras et al., 2005). Thepatternobserved in thepresentstudyagreedwiththedevelopment of memorycells. Afterthechallenge, IV vaccinatedpigsshowed a significantincrease in theneutralizingantibodiesproduction –in proportion of positive pigs and in mean titres-.

  10. EXPERIMENT 2: Development of PRRSV-specificimmune responses afterattenuatedvaccine (MLV) primo-immunizationfollowedwith a MLV orPROGRESSIS® recallvaccination VACCINATION SCHEDULE  BALANCE SAFETY/EFICACY 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)

  11. TOTAL ANTIBODIES (ELISA Idexx) Challenge

  12. NEUTRALIZING ANTIBODIES (VNT) • PROPORTION OF POSITIVE PIGS • MEAN TITRES (log2) ± STAND. DEV

  13. CELL-MEDIATED IMMUNITY (ELISPOT IFNγ) a† a a Challenge ab† a PRRSV-specific IFN-γ-SC / 106 PBMC a b a b Re-vaccination a ab b MLV Primo-immunization b ab b b c b b c

  14. VIREMIA by RT-PCR No significantdifferencesamongvaccinatedgroups

  15. Development of PRRSV-specificimmune responses afterattenuatedvaccine (MLV) primo-immunizationfollowedwith a MLV or PROGRESSIS® recallvaccination IV IV MLV MLV After a MLV primo-immunization: IV re-vaccinationinduced a significantincreasein thedevelopment of cell-mediatedimmunity(anamnestic response). Afterthechallenge, MLV+IV+IVgroupdevelopedthehighest PRRSV-specificimmune responses (cell-mediatedimmunity and neutralizingantibodies). Allthevaccinationschedulesreached similar levels of protection. VACCINATION SCHEDULE  BALANCE SAFETY/EFICACY

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