In vitro immunomodulatory effects of acidic exopolysaccharide produced by Lactobacillus planetarium JLAU103 on RAW264.7 macrophages

Previous work from our research group has isolated and purified an acidic exopolysaccharide (named EPS103) from Lactobacillus plantarum JLAU103, which had strong in vitro antioxidant activity. In this study, we investigated the in vitro immunomodulatory activity of EPS103 in RAW264.7 macrophages with or without lipopolysaccharide (LPS) activation. The results showed that EPS103 enhanced the phagocytic activity of RAW264.7 macrophages and promoted the release of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and nitric oxide (NO) of RAW264.7 macrophages. Moreover, EPS103 reduced the excessive release of IL-6, TNF-α, prostaglandin E2 (PGE2), and NO, as well as inhibited the mRNA expression of IL-6, TNF-α, cyclooxygenase-2 (COX-2), and inducible NO synthase (iNOS) of RAW264.7 macrophages activated by LPS. In mechanistic studies, EPS103 exerted immunomodulatory activity via the nuclear factor-kappa B (NF-κB) signaling pathway. These findings suggest that EPS103 possesses potent dual immunomodulatory activities and could be further developed as new products for functional foods or medicines.