Immunomodulatory activity of selenium exopolysaccharide produced by<i>Lactococcus lactis</i>subsp.<i>Lactis</i>

Abstract

Exopolysaccharide (EPS) was isolated and purified from Lactococcus lactis subsp. Lactis culture and then selenium chloride oxide (SeCl2O) was added to synthesise selenium-exopolysaccharide (Se-EPS). This study sought to evaluate the immunomodulatory effects of EPS and Se-EPS on the activity of peritoneal macrophages and spleen lymphocytes. In mouse peritoneal macrophages, the EPS and Se-EPS enhanced phagocytosis and increased nitric oxide (NO), IFN-γ, IL-1, IL-6 and IL-12 secretion, but not IL-10 levels. Preliminary in vitro tests revealed that EPS and Se-EPS stimulated mouse spleen lymphocyte proliferation, and strongly improved levels of TNF-α, IL-2 and IL-6 mRNA in spleen cells. These findings indicate that EPS and Se-EPS can enhance the immune response via enhanced macrophage and spleen lymphocyte stimulation. Se-EPS showed stronger immunomodulatory activity than EPS.