Bifidobacterium animalis ssp. lactis Bb12 induces IL‐10 through cell membrane‐associated components via TLR2 in swine

Aim To investigate the role of Toll‐like receptor 2 (TLR2) in interleukin‐10 (IL‐10) production induced by Bifidobacterium animalis ssp. lactis Bb12 (Bb12) in swine immune cells. Methods and Results Blood‐monocytes and cells from mesenteric lymph nodes were obtained from pigs and cultured with live Bb12 for 4 and 12 h. Transcript levels of IL‐10 and TLR2 were analysed. Furthermore, TLR2 was blocked to determine its participation in IL‐10 production. TLR2 blockade was achieved with neutralizing antibodies, followed by stimulation with Bb12. Bifidobacteria induced IL‐10 production in both swine monocytes and mesenteric cells. Monocytes with TLR2 blockade had a decrease in IL‐10 transcripts, while mesenteric cells did not. Bacterial cell wall components were responsible for Bb12‐induced IL‐10 production since no IL‐10 was detected in the culture supernatant. Conclusions We demonstrated that IL‐10 production is largely mediated through the recognition of Bb12 structures by TLR2, as bacterial metabolites in the culture supernatant failed to induce IL‐10 expression. Significance and Impact of the Study The present study provides evidence for the potential use of Bb12 in the swine industry; these bacteria can also be used as additional method to treat intestinal inflammation and enhance intestinal health in pigs.