ABSTRACT
Objective To extract and purify a polysaccharide SEP from eggs of sea urchin Strongylocentrotus nudus. and to determine its purity, molecular weight and immunological activity in vitro. Methods The orthogonal design was employed to obtain the best possible combination of the critical parameters for polysaccharide extraction. By ultrafiltration, DE-AE Sepharose Fast Flow anion-exchange chromatography and Sephacryl S-400 gel filtration chromatography, the deproteinated crude polysaccharide was purified. The homogeneity of SEP was proved by HPLC, polyacrylamide gel electrophoresis and paper chromatography. Its molecular weight was determined by HPGPC in reference to standVd T-series Dextran. Lymphocyte proliferation assay was made to investigate the immuno-modulating activity of SEP. Results and Conclusion The results indicated SEP was a homogeneous polysaccharide. Its molecular weight was about 1950KD. SEP increased remarkably spleen lymphocyte proliferation. The homogeneous polysaccharide SEP showed significantly immunological activity in vitro.