Immunomodulatory Activities Of Selenium Exopolysaccharide Produced By Lactococcus Lactis Subsp.Lactis

Exopolysaccharide (EPS) is viscous polysaccharose or capsular polysaccharidewhich is secreted outside the lactobacillus during culture. In this study, EPS was isolatedand purified from Lactococcus lactis subsp. Lactis culture, followed by adding Selenium chlorideoxide to the EPS to synthesize selenium-exopolysaccharide (Se-EPS).Macrophages are massively distributed in tissues, produced by the differentiation ofmonocytes. Macrophages play important role in host immune defenses line and keep thebalance of body together with Monocytes. The main role of them is to phagocytosebacterias, pathogen, even cancer cells. Macrophages function in both non-specificdefense (innate immunity) and specific defense mechanisms (adaptive immunity). Thespleen is one of the most important immune organs and the source of lymphocytes. T and Blymphocytes, which play vital role in immune system, are two principle cells of spleen. They havenumerous biological functions. Once they are actived, they could be responsible for cellularimmunity to inhibit or kill target cell. They could also release lymphatic to kill invading antigenthrough humoral immune response.In this study, we took Se-EPS as research target and analysed the effect of Se-EPS onimmunological activity by culturing mouse spleen cells and mouse peritoneal macrophages invitro.Main results are as follows:1The optimal functioning time of Se-EPS is48h. Se-EPS have ability to improve thephagocytosis and NO production of macrophage. Through researches on effects of Se-EPS onmouse cytokines, we found, Se-EPS enhanced proinflammatory factor (IFN-γ, IL-1, IL-6andIL-12) secretion, but not anti-inflammatory (IL-10) secretion. The activities of Se-EPS were higherthan EPS, obviously.2Vitro tests revealed that EPS and Se-EPS could stimulate mouse B and T lymphocyteproliferation. The ELISA kits were used to investigate the cytokine secretion. Treatment of spleenlymphocyte with250–800mg/mL Se-EPS resulted in an increased production of IFN-γ and IL-1.When treated with Se-EPS, concentration range from100–500mg/mL，we found Se-EPS couldcause TNF-α, IL-2and IL-6secretion improvement in a dose dependent manner and achieved maxmine value at800mg/mL, which could be further certified by TNF-α, IL-2and IL-6mRNAexpression in the study.