Activation of macrophages by an exopolysaccharide isolated from Antarctic Psychrobacter sp.B-3

摘要

An exopolysaccharide (EPS) was isolated and purified from an Antarctic psychrophilic bacterium B-3,identified as Psychrobacter sp.,and the activation of RAW264.7 cells by B-3 EPS was investigated.The results show that B-3 EPS,over a certain concentration range,promoted cell viability,nitric oxide production,tumor necrosis factor (TNF)α secretion,and phagocytic ability.Furthermore,TAK-242,an inhibitor of the toll-like receptor 4 (TLR4) significantly reduced nitric oxide production by these cells after stimulation with B-3 EPS.Moreover,B-3 EPS induced p65 phosphorylation and Iκ Bα degradation in these cells.In conclusion,B-3 EPS might have activated RAW264.7 cells by combining with TLR4 on cell surface and triggering activation of NF-κB signaling pathways,implying that this EPS could activate macrophages and regulate initial immune response.