Immunomodulatory activities of sulfated Cyclocarya paliurus polysaccharides with different degrees of substitution on mouse spleen lymphocytes

Two sulfated polysaccharides SCP3 and SCP5 with degree of substitution (DS) 0.45 and 0.13 were obtained by modifying the Cyclocarya paliurus polysaccharide (CP) with chlorosulfonic acid-pyridine method. Results demonstrated that the physicochemical properties, molar ratios of monosaccharide composition, molecular weights, and in vitro immunomodulatory activity were changed after being sulfated. Splenocytes proliferation assay showed that both CP and sulfated polysaccharides have immunomodulatory, while sulfated polysaccharides were stronger. CP mainly stimulate the production of the Th1-type cytokines, SCP3 and SCP5 not only significantly enhanced the secretion level of Th1-type cytokines, but also promote the Th2-type cytokines. Sulfated polysaccharides could significantly stimulate splenic lymphocyte proliferation synergistically with ConA or LPS. SCP3 significantly promoted the proliferation of T lymphocytes, while SCP5 stimulated the proliferation of B lymphocytes, which might be related to the DS. These results indicated that sulfation could improve the immune-enhancing effects of CP and different DS has different immunomodulatory activity.