Selenium Myricaria germanica Polysaccharides-based Nanoparticles to Improve Immune Activity

In this study, a nano-drug delivery system based on poly(lactic-co-glycolic acid) (PLGA) that modified selenated Myricaria germanica polysaccharide (sMGP) was developed to enhance immune responses. At the O to W1 ratio of 8.29, the W2 to primary emulsion ratio of 7.62, and the concentration of PLGA was 37.94 mg/mL, the entrapment efficiency of sMGP-PLGA was 90.27%. In vitro, at the concentration of 3.125-25 µg/mL, sMGP-PLGA significantly enhanced the phagocytosis of RAW264.7 macrophages, facilitated the upregulation of surface molecules CD40 and CD86, and increased the secretion of cytokines interferon-gamma (IFN-γ) and interleukin (IL)-4, as well as the gene expression levels of toll-like receptor 4 and nuclear factor kappa B. In vivo sMGP-PLGA significantly increased the Newcastle disease antibodies, IFN-γ, and IL-6 levels, activated the immune functionality of spleen, thymus, and bursa of Fabricius, and improved the organ index. Meanwhile, sMGP-PLGA promoted the proliferation of T and B lymphocytes. These findings indicate that sMGP-PLGA could enhance the immune activity.