CONICET | Buscador de Institutos y Recursos Humanos

Lactobacillus jensenii TL2937 (Lj) functionally modulates porcine intestinal immune system inducing tolerance against LPS challenge. The interaction of Lj with porcine antigen presenting cells (APC) from blood and Peyer´s patches (PPs) was evaluated by studying their phagocytic activity, and the expression of activation molecules and cytokines. In addition, the role of TLR2 in the recognition of Lj was assessed. Porcine PPs APCs were obtained by a magnetically activated cell sorting separation system while blood APCs were generated in vitro by standard procedures. Interaction of Lj and L. plantarum TL2766 (Lp, negative control) with APCs was evaluated with electron microscopy and flow cytometry. ELISA and RT-PCR were used to evaluate expression of cytokines. Anti-porcine TLR2 blocking antibodies and HEKTLR2 transfectants were used to study the role of this receptor in Lj-APCs interaction. Lj activated HEKTLR2 transfectants while this effect was not observed in Lp. PPs and blood APCs efficiently phagocyted Lj in a TLR2-dependent manner and upregulated the expression of MHC-II and CD80/86. Lj significantly increased IL-1β, IL-12 and IL-10 in CD172ahighCD11R1+ and CD172alowCD11R1+ cells from both PPs and blood. Lp was less efficiently phagocyted and, although it increased MHC-II, it had a significant lower capacity to improve IL-1β, IL-12 and IL-10 in CD172ahighCD11R1+ and CD172alowCD11R1+ cells. L. jensenii TL2937 is efficiently recognized and phagocyted by porcine PPs or blood APCs in a TLR2-dependent manner. Activation of TLR2 by the TL2937 strain functionally modulate APCs, which will explain in part, its immunoregulatory capacities observed in vivo.