Differential immune-stimulatory effects of LTAs from different lactic acid bacteria via MAPK signaling pathway in RAW 264.7 cells

pLTA and rLTA moderately induced TNF-α, IL-10, and NO production compared with stimulation of RAW 264.7 cells with dLTA and sLTA. Similar results were obtained for the mRNA and protein expression levels of iNOS. Western blot analysis showed that treatment of cells with pLTA or rLTA resulted in minimal phosphorylation of ERK, JNK and p38 MAPK while, dLTA and sLTA were strong activators of MAPK signaling. In addition, the glycolipid structure of LTAs was found to be composed of different fatty acid chain groups and lengths. Taken together, these results suggest that the differential immuno-stimulatory effects of LTAs isolated from different lactobacillus species may be related to their different ability to activate the MAPK signaling pathway, which are modulated by a unique glycolipid structure of LTA.