Inhibitory effects of Lactobacillus plantarum lipoteichoic acid (LTA) on Staphylococcus aureus LTA-induced tumor necrosis factor-alpha production

Staphylococcus aureus is a common etiologic agent for Gram-positive sepsis, and its lipoteichoic acid (LTA) may be important in causing Gram-positive bacterial septic shock. Here, we demonstrate that highly purified LTA (pLTA) isolated from Lactobacillus plantarum inhibited aureus LTA (aLTA)-induced TNF-alpha production in THP- cells. Whereas pLTA scarcely induced TNF-alpha production, aLTA induced excessive TNF-alpha production. Interestingly, aLTA-induced TNF-alpha production was inhibited by pLTA pretreatment. Compared with pLTA, aLTA induced strong signal transduction through the MyD88, NF-kappaB, and MAP kinases. This signaling, however, was reduced by a pLTA pretreatment, and resulted in the inhibition of aLTA-induced TNF-alpha production. Whereas dealanylated LTAs, as well as native LTAs, contributed to TNF- induction or TNF-alpha reduction, deacylated LTAs did not, indicating that the acyl chain of LTA played an important role in the LTA-mediated immune regulation. These results suggest that pLTA may act as an antagonist for aLTA, and that an antagonistic pLTA may be a useful agent for suppressing the septic shock caused by Gram-positive bacteria.