Efficacy and safety of a combined Porcine Circovirus and Mycoplasma hyopneumoniae vaccine in finishing pigs

The safety and protective efficacy of a new one dose combination vaccine containing Porcine Circovirus type 2 (PCV2) and M. hyopneumoniae antigens – Porcilis® PCV M Hyo - was evaluated in laboratory studies and under field conditions. Vaccination resulted in a moderate temperature increase on the day of vaccination and mild systemic and local reactions were found in only a low percentage of the vaccinated pigs. The local reactions observed were small (max. 2 cm) and transient (max. 1 day). In short term (onset of immunity) and long term (duration of immunity) challenge studies with the individual pathogens, the vaccine significantly reduced the PCV2 load in lymphoid tissue and lungs and M. hyopneumoniae-induced lung lesions. In a placebo-controlled field trial on a farm where both PCV2 and M. hyopneumoniae were present, vaccination of piglets at 3 weeks of age resulted in a reduction of PCV2 viremia and shedding and lower lung lesion scores at slaughter. In addition, a positive effect on the average daily weight gain (+ 34 g/day) in the finishing phase was observed. It can therefore be concluded that this new ready to use combination vaccine is safe and efficacious against PCV2 and M. hyopneumoniae single and combined infections

T-Cell Cytokine Response in Salmonella Typhimurium-Vaccinated versus Infected Pigs

Vaccination with the live attenuated vaccine Salmoporc is an effective measure to control Salmonella Typhimurium (STM) in affected swine populations. However, the cellular immune response evoked by the Salmoporc vaccine including differences in vaccinated pigs versus non-vaccinated pigs upon STM infection have not been characterized yet. To investigate this, tissue-derived porcine lymphocytes from different treatment groups (vaccination-only, vaccination and infection, infection-only, untreated controls) were stimulated in vitro with heat-inactivated STM and abundances of IFN-γ, TNF-α and/or IL-17A-producing T-cell subsets were compared across organs and treatment groups. Overall, our results show the induction of a strong CD4+ T-cell response after STM infection, both locally and systemically. Low-level induction of STM-specific cytokine-producing CD4+ T cells, notably for the IFN-γ/TNF-α co-producing phenotype, was detected after vaccination-only. Numerous significant contrasts in cytokine-producing T-cell phenotypes were observed after infection in vaccinated and infected versus infected-only animals. These results suggest that vaccine-induced STM-specific cytokine-producing CD4+ T cells contribute to local immunity in the gut and may limit the spread of STM to lymph nodes and systemic organs. Hence, our study provides insights into the underlying immune mechanisms that account for the efficacy of the Salmoporc vaccine