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.