Inhibitory Effect of Lipoteichoic Acid Derived from Three Lactobacilli on Flagellin-Induced IL-8 Production in Porcine Peripheral Blood Mononuclear Cells

Abstract

Probiotics in livestock feed supplements are considered to be an alternative to antibiotics. However, effector molecules responsible for the beneficial roles of probiotics in pigs are in general not well known. Thus, this study demonstrated that a well-known virulence factor, flagellin ofSalmonella typhimurium, significantly induced IL-8 production in porcine peripheral blood mononuclear cells, whereas lipoteichoic acid (LTA), a major cell wall component of Gram-positive bacteriaLactobacillus plantarum,L. casei, andL. rhamnosusGG, effectively inhibited flagellin-induced IL-8 production at mRNA and protein levels. However, the lipoproteins ofL. plantarum,L. casei, andL. rhamnosusGG did not suppress flagellin-induced IL-8 production. While D-alanine-deficientL. plantarumLTA inhibited flagellin-induced IL-8 production,L. plantarumLTA deficient in both D-alanine and acyl chains failed to inhibit it; this suggests that the acyl moieties ofL. plantarumLTA are essential for inhibiting flagellin-induced IL-8 production. Taken together,L. plantarumLTA plays an important role in improving anti-inflammatory responses of porcine peripheral blood mononuclear cells.