Heterologous cell-mediated immunity of PRRS in pigs vaccinated with UNISTRAIN® PRRS via the IM and ID routes

Startseite Know-how Heterologous cell-mediated immunity of PRRS in pigs vaccinated with UNISTRAIN® PRRS via the IM and ID routes

Heterologous cell-mediated immunity of PRRS in pigs vaccinated with UNISTRAIN® PRRS via the IM and ID routes

Intradermal (ID) vaccination opens new horizons for animal health and animal welfare. UNISTRAIN® PRRS vaccine can be administered via both the intramuscular (IM) and ID routes and has demonstrated clinical protection against both genotype I and II highly pathogenic PRRS challenges.

At the same time, UNISTRAIN® PRRS showed a strong heterologous cell-mediated immune response against different European strains in pigs vaccinated either IM or ID. Thus, UNISTRAIN® PRRS demonstrated heterologous protection for the control of PRRS in pigs via both ID and IM vaccination.

Despite the fact that mechanisms of immunogenicity and the development of clinical protection by PRRS vaccines have not been clearly elucidated yet, UNISTRAIN® PRRS showed different degrees of heterologous protection even against field strains of different genotypes(1). The specific ability of the virus used in the immunization to induce cellular immunity could be an important factor for heterologous protection. Cell-mediated responses after PRRS vaccination could be responsible for limiting the duration of viraemia and consequently the transmission of PRRS in pigs (2).

In order to assess cell-mediated response in pigs vaccinated with UNISTRAIN® PRRS, PRRS-free gilts were vaccinated either ID or IM. Frequencies of PRRS-specific IFN-Ɣ-secreting cells (IFN-Ɣ-sc) were measured to evaluate the heterologous responses against 5 different European isolates from clinical outbreaks in the field. Isolated PRRS in pigs came from different European countries (Slovakia, UK, Hungary Spain and Italy) and were isolated between 2005 and 2011, so geographical and temporal diversity were studied.

Results showed strong IFN-Ɣ-sc activity for all strains and both ID and IM vaccination routes. For the ID route, a peak of IFN-Ɣ-sc response was observed at 28 days post vaccination (pv) for all strains. At the same time, the ID route showed a higher response than the IM route at different times pv:

According to these results we can affirm that the VP-046-BIS PRRS strain, the vaccine virus of UNISTRAIN®PRRS, produces a strong cellular heterologous immunogenicity when applied both intramuscularly and intradermally. At the same time, experimental and field trials also demonstrated the in vivo efficacy of UNISTRAIN® PRRS for ID and IM vaccination.

REFERENCES: 

1. Roca et al. Vet. J. (2012) 193:92-6.
2. Pileri et al. Vet. Microbiol. (2014) 175:7-16.