Vaccines (Nov 2022)

Efficacy and Safety of Native and Recombinant Zona Pellucida Immunocontraceptive Vaccines Formulated with Non-Freund’s Adjuvants in Donkeys

  • Hilari French,
  • Lorenzo Segabinazzi,
  • Brittany Middlebrooks,
  • Erik Peterson,
  • Martin Schulman,
  • Robyn Roth,
  • Michael Crampton,
  • Anne Conan,
  • Silvia Marchi,
  • Trevor Gilbert,
  • Darryn Knobel,
  • Henk Bertschinger

DOI
https://doi.org/10.3390/vaccines10121999
Journal volume & issue
Vol. 10, no. 12
p. 1999

Abstract

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This study aimed to test zona pellucida (ZP) vaccines’ immunocontraceptive efficacy and safety when formulated with non-Freund’s adjuvant (6% Pet Gel A and 500 Μg Poly(I:C)). Twenty-four jennies were randomly assigned to three treatment groups: reZP (n = 7) received three doses of recombinant ZP vaccine; pZP (n = 9) received two doses of native porcine ZP; and Control group (n = 8) received two injections of placebo. Jennies were monitored weekly via transrectal ultrasonography and blood sampling for serum progesterone profiles and anti-pZP antibody titres. In addition, adverse effects were inspected after vaccination. Thirty-five days after the last treatment, jacks were introduced to each group and rotated every 28 days. Vaccination with both pZP and reZP was associated with ovarian shutdown in 44% (4/9) and 71% (4/7) of jennies, 118 ± 33 and 91 ± 20 days after vaccination, respectively (p > 0.05). Vaccination delayed the chances of a jenny becoming pregnant (p = 0.0005; Control, 78 ± 31 days; pZP, 218 ± 69 days; reZP, 244 ± 104 days). Anti-pZP antibody titres were elevated in all vaccinated jennies compared to Control jennies (p < 0.05). In addition, only mild local injection site reactions were observed in the jennies after treatment. In conclusion, ZP vaccines formulated with non-Freund’s adjuvant effectively controlled reproduction in jennies with only minor localised side effects.

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