Peer-Reviewed Journal Details
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Sandra Vreman, Norbert Stockhofe-Zurwieden, Ditta J.Popma-de Graaf, Huub, F.J. Savelkoul, C.Barnier-Quer, N. Collin, Damien Collins, Dennis McDaid, Anne C.Moore, Johanna M.J.Rebel
Veterinary Immunology and Immunopathology
Immune responses induced by inactivated Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) vaccine in neonate pigs using different adjuvants
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neonate piga djuvant Toll-like receptor agonist skin vaccination PRRSV
Vaccination of neonate pigs could be supportive to prevent porcine reproductive and respiratory syndrome virus (PRRSV), which is an important porcine pathogen causing worldwide welfare and health problems in pigs of different age classes. However, neonatal immunity substantially differs to adults, thus different vaccines may be required in neonate pigs. We examined if the immunogenicity and efficacy of inactivated PRRSV (iPRRSV) vaccines in neonate pigs could be improved with adjuvants containing (oil-in water (O/W) emulsions with or without Toll-like receptor (TLR) agonists) and by altering the delivery route from intramuscular (i.m.) to the skin. Three-day-old PRRSV-naïve piglets (n = 54, divided in 6 groups) received a prime vaccination and a booster vaccination four weeks later. The vaccine formulations consisted of different O/W emulsions (Montanide™ ISA28RVG (ISA28), a squalene in water emulsion (SWE) for i.m. or a Stable Emulsion (SE) with squalene for skin vaccination) and/or a mixture of TLR1/2, 7/8 and 9 agonists (TLRa) combined with iPRRSV strain 07V063. These vaccines were delivered either i.m. (ISA28, SWE, TLRa or SWE + TLRa) or into the skin (skiSE + TLRa) with dissolving microneedle (DMN)-patches. All animals received a challenge with homologous PRRSV three weeks after booster vaccination. Specific antibodies, IFN-γ production and viremia were measured at several time-points after vaccination and/or challenge, while lung pathology was studied at necropsy. After booster vaccination, only ISA28 induced a specific antibody response while a specific T-cell IFN-γ response was generated in the SWE group, that was lower for ISA28, and absent in the other groups. This suggests that prime vaccination in neonates induced a specific immune response after booster vaccination, dependent on the emulsion formulation, but not dependent on the presence of the TLRa or delivery route. Despite the measured immune responses none of the vaccines showed any efficacy. Further research focused on the early immune response in draining lymph nodes is needed to elucidate the potential of TLRa in vaccines for neonate pigs.
Grant Details