Twelve healthy 4-week-old piglets without P. multocida antibodies were randomly divided into three groups (n = 4 each). The vaccinated groups were immunized intramuscularly with 2 mL of (1) rPMT-NC + CpG, (2) rPMT-NC + w/o/w, or (3) PBS (Table 1 ). Piglets were boosted with the same vaccine at 2 weeks after the primary immunization. All piglets were challenged intranasally with 1 × 108 CFU/mL P. multocida serotype A 4 weeks after primary immunization [16 (link)]. The antibody titre was detected by blood samples taken at 0, 2 and 4 weeks after primary immunization. The piglets were monitored daily for clinical signs, body temperature (fever was defined as rectal temperature > 39.5 °C), and body weight and were sacrificed for necropsy 14 days after challenge. Pathological examination was performed by the Veterinary Pathology Department of NPUST, and the lesion score was calculated based on the area of lesions in an organ, where no lesion = 0, lesion area < 33% = 1, lesion area 33–66% = 2, and lesion area > 66% = 3 [3 (link)].
| Vaccinea | Adjuvant |
|---|---|
| Trial 1. Plasmid CpG adjuvant effect test | |
| 1. rPMT-NCb + CpG | CpG (200 μg/mL) |
| 2. rPMT-NC + w/o/w | w/o/w |
| 3. Control (PBS) | – |
| Trial 2. rSly adjuvant dose-dependent test | |
| 4. rPMT-NC + w/o/w + rSly | rSly (100 μg/mL) |
| 5. rPMT-NC + w/o/w + rSly | rSly (150 μg/mL) |
| 6. Control (PBS) | – |
| Trial 3. Comparison with various adjuvants | |
| 7. rPMT-NC + w/o/w + rSly | rSly (100 μg/mL) |
| 8. rPMT-NC + w/o/w + CpG | CpG (200 μg/mL) |
| 9. rPMT-NC | – |
| 10. Commercial vaccinec | Al-gel |
| 11. Control (PBS) | – |
aPig immunizaction vaccine with 2 mL by I.M.
brPMT-NC (200 μg/mL).
cIngredient: B. bronchiseptica (1 × 109 CFU), P. multocida type A (1 × 109 CFU).
P. multocida type D (1 × 109 CFU), rsPMT/tox1 (20 μg), rsPMT/tox2 (20 μg), rsPMT/tox7 (20 μg), Adjuvant: Al-gel.
Free full text: Click here
