Screening on the immune-enhancing active site of Siberian solomonseal rhizome polysaccharide

The total Siberian solomonseal rhizome polysaccharide (SRPSt) and four fractional SRPS30, SRPS50, SRPS70 and SRPS80, were extracted by one-step or stepwise ethanol precipitation method. In test in vitro, their effects on chicken peripheral lymphocytes proliferation were compared. The result showed that SRPS70 and SRPS50 presented better effect. In test in vivo, 14-day-old chickens were injected, respectively, with SRPS50, SRPS70 and SRPSt, at the first vaccination of ND vaccine, once a day for three successive days. On days 7, 14, 21 and 28 after the first vaccination, the peripheral lymphocytes proliferation and antibody titer were determined. The result indicated that lymphocyte proliferation and antibody titers in SRPS50 group at all time points were the highest, significantly higher than those of non-adjuvant control group and most of another two SRPSs groups. These results confirmed that SRPS50 possessed the strongest action and was the immune-enhancing active site of SRPS.