Evaluation of PRRSv specific, maternally derived and induced immune response in Ingelvac PRRSFLEX EU vaccinated piglets in the presence of maternally transferred immunity

Abstract

In this study, we analyzed PRRS virus (PRRSv) specific lymphocyte function in piglets vaccinated with Ingelvac PRRSFLEX EU® at two and three weeks of age in the presence of homologous maternal immunity. Complete analysis of maternal immunity to PRRSv was evaluated postpartum, as well as passive transfer of antibodies and T cells to the piglet through colostrum intake and before and after challenge with a heterologous PRRSv at ten weeks of age. Maternal-derived antibodies were detected in piglets but declined quickly after weaning. However, vaccinated animals restored PRRSv-specific antibody levels by anamnestic response to vaccination. Cell analysis in colostrum and milk revealed presence of PRRSv-specific immune cells at suckling with higher concentrations found in colostrum than in milk. In addition, colostrum and milk contained PRRSv-specific IgA and IgG that may contribute to protection of newborn piglets. Despite the presence of PRRSv-specific Peripheral Blood Mononuclear cells (PBMCs) in colostrum and milk, no PRRSv-specific cells could be detected from blood of the piglets at one or two weeks of life. Nevertheless, cellular immunity was detectable in pre-challenged piglets up to 7 weeks after vaccination while the non-vaccinated control group showed no interferon (IFN) γ response to PRRSv stimulation. After challenge, all piglets developed a PRRSv-specific IFNγ-response, which was more robust at significantly higher levels in vaccinated animals compared to the primary response to PRRSv in non-vaccinated animals. Cytokine analysis in the lung lumen showed a reduction of pro-inflammatory responses to PRRSv challenge in vaccinated animals, especially reduced interferon (IFN) α levels. In conclusion, vaccination of maternally positive piglets at 2 and 3 weeks of age with Ingelvac PRRSFLEX EU induced a humoral and cellular immune response to PRRSv and provided protection against virulent, heterologous PRRSv challenge.

Impact of maternally derived immunity on immune responses elicited by piglet early vaccination against the most common pathogens involved in porcine respiratory disease complex

“…However, it must be considered that lack of demonstrated commercial vaccine effectiveness is unlikely to be published in the literature. Furthermore, it would be also worthy to investigate if the existence of antigen-specific CMI of maternal origin in the neonatal piglet can influence the development of vaccine-induced immunity, particularly in those cases where the piglet is vaccinated very early [ 129 ].…”

Correlation of Neutralizing Antibodies (NAbs) between Sows and Piglets and Evaluation of Protectability Associated with Maternally Derived NAbs in Pigs against Circulating Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) under Field Conditions

“…While the high and middle NAbs groups could induce superior neutralizing antibodies with respect to the low NAbs group, only those pigs in the groups with high NAbs titers exhibited exceptional survival rates at 10 weeks of age. Meanwhile, antiviral, modulatory, humoral and cellular immunity coregulating the dynamics of cytokines, such as TNF-α, IFN-γ, IL-10, TGF-β, IL-12, IL-4 and IL-6 might also play critical roles during the inflammatory period against PRRSV [ 10 , 12 , 13 , 14 , 15 , 24 , 25 , 26 , 27 , 28 , 29 ]. In addition, the existence of single nucleotide polymorphisms (SNPs) in host genes, such as GBP-1, Mx-1 and CD163, has also been attested to alleviate the viremia during PRRSV infections [ 30 , 31 ].…”

Maternal Autogenous Inactivated Virus Vaccination Boosts Immunity to PRRSV in Piglets

“…These IFN-γ producing cells are highly important in anti-viral responses, including in PRRSV [ 19 , 21 ]. This vaccination also induced serum anti-PRRSV IgG, which was detectable after six weeks of age for unvaccinated piglets and remained stable in vaccinated piglets prior to challenge; yet, IFN-γ secreting cells could not be distinguished from background levels in pre-weaned piglets [ 22 ]. While the use of MLVs is an industry standard, a combined vaccination regimen of an MLV prime and AIV boost vaccination seems promising to overcome each of the downsides of independently using MLVs and AIVs.…”