A Comparison of Characterization and Its Actions on Immunocompetent Cells of Polysaccharides from Sijunzi Decoction

Sijunzi decoction (SJZD) is a classic recipe in Traditional Chinese Medicine (TCM) with strong immune-enhancement activity. To further understand the characterization and immunomodulatory effect of polysaccharides from SJZD, the monosaccharide compositions of crude polysaccharide (SJZDP), polysaccharide fraction (S-3), and homogeneous polysaccharide (S-3-AG) from SJZD were compared by GC analysis, as well as their immunomodulatory effects on Peyer's patch cells, splenocytes, and macrophages which are related to intestinal immunity, specific immunity, and nonspecific immunity. The results showed that S-3-AG mainly contained Ara with a proportion of 38.9%, while Glc accounted for the largest proportion in S-3 (55.6%) and SJZDP (87.6%). The SJZDP, S-3, and S-3-AG all showed strong capability to stimulate Peyer's patch cells to proliferate and produce IgA and promoted the proliferation and IFN-γ production of splenocytes and increased the NO production and TNF-α production of macrophages. However, S-3 and S-3-AG were able to stimulate splenocytes to secret IL-4, SJZDP had no effect on IL-4 production of splenocytes in the tested concentrations. In addition, S-3 could stimulate the phagocytic activity of macrophages, and S-3-AG restrained the proliferation of macrophages at the concentration of 50–200 µg/mL. These results suggested that SJZDP, S-3, and S-3-AG might have different immunomodulatory effects on intestinal immunity, specific immunity, and nonspecific immunity due to their different monosaccharide compositions. It will provide references for the material basis and mechanism of SJZD immunomodulation activity.