Implication of TLR in the activity of the macrophages in response to the stimulation with probiotic bacteria

LEMME DUMIT, JOSÉ MARÍA; PERDIGÓN, GABRIELA; MALDONADO GALDEANO, CAROLINA

Congreso; LVIII Reunión Científica Anual Sociedad Argentina de Investigación Clínica (SAIC)-LX Reunión Anual Sociedad Argentina de Inmunología (SAI).; 2013

The innate immune system is triggered when the pattern recognition receptors (PRRs) on immune cells, recognized the pathogen-associated molecular patterns. These molecules belong to the Toll-like receptors (TLRs). The activation of TLR induces pro/anti-inflammatory cyto- and chemokines secretion that link the innate and adaptive immune response. AIM: To evaluate in mice the importance of TLRs signaling in phagocytic activity (PA) of peritoneal (MQP), Peyer´s patches (MQPP) and spleen (MQS) macrophages after probiotic stimulation. BALB/c mice received as feeding supplementation a probiotic bacteria Lactobacillus casei CRL-431 or a probiotic fermented milk (PFM), administered for 7 and 5 days respectively. The MQP, MQPP and MQS samples were taken at the end of the feeding period and were to confront with both TLR2 and TLR4 agonists and antagonists. PA in MQP, MQS and MQPP were determined. In vitro the production of IL-6 was determined by ELISA in the supernatant of MQP, MQS and MQPP stimulated with the probiotic bacteria or with PFM, confronted previously with TLR2 and TLR4 antagonist. Results: Probiotic and PFM administration increased the PA of MQP and MQS, this activity was enhanced with TLR agonists (p≤0,01). MQPP not showed the same behavior when they were confronted with agonists and antagonists of TLRs, even in the mice given the probiotic or PFM. The IL-6 levels in the MQP and MQPP supernatant showed increases when the cells were blocked with TLRs antagonists and them they were stimulated with PFM (P≤0,001). Conclusion: The results showed that TLR2 and TLR4 are involved in the macrophages signal stimulation by probiotics in PA. However compared to TLR2 and TLR4 antagonist, probiotics were not able to restore the PA. These results showed that the Toll pathway would not be the only one involved in such activity. Regarding the production of cytokines, probiotic bacteria were effective to send signals of activation through these TLRs pathway.