FRACTIONATION AND CHEMICAL-PROPERTIES OF IMMUNOMODULATING POLYSACCHARIDES FROM ROOTS OF DIPSOCUS ASPEROIDES

A crude polysaccharide fraction (DAP-1) was prepared from roots of Dip sacus asperoides by hot water extraction and EtOH precipitation, and t ested for anti-complementary activity, mitogenic activity of lymphocyt es, and effects on acid phosphatase and phagocytic activities of macro phages. DAP-1 showed not only anti-complementary activity but also a s timulating effect on the mitogenic activity of lymphocytes. DAP-1 also significantly suppressed the phagocytic activity of macrophages. Alth ough DAP-1 directly stimulated the mitogenecity of lymphocytes, it had no effect on lipopolysaccharide-or concanavalin A-induced mitogenic a ctivity of lymphocytes. Periodate oxidation and pronase digestion sugg ested that the polysaccharide moiety in DAP-1 contributed to the expre ssion of its anticomplementary and mitogenic activities and that the p rotein moiety in DAP-1 was responsible for its effect on phagocytosis. DAP-1 gave three polysaccharide fractions (DAP-2, 3, and 4) by fracti onation using cetyltrimethylammonium bromide. All the fractions had po tent anti-complementary activity, but showed different stimulating or suppressive effects on the proliferation of lymphocytes, phagocytosis, or acid phosphatase activity. Three potent anti-complementary polysac charides (DAP-41-1a, DAP-41-1b, and DAP-4IIa-1) were purified from DAP -4 by anion-exchange chromatography, gel filtration, and HPLC. DAP-41- 1a, I-lb, and IIa-1 consisted of Ara, Rha, Xyl, Gal, Glc and GlcA in a molar ratio of 1.0:0.7:1.0:18.6:22.2: nil; 1.0:0.1:0.3:19.3: 26.8:nil ; and 3.7:trace: 0.6:26.3:5.5:1.0; respectively. Among the polysacchar ides, only DAP-4IIa-1 reacted with beta-glucosyl-Yariv antigen. Methyl ation analysis indicated that DAP-41-1a mainly comprised 4-linked Gal and 3-, 4-, and 6-linked Glc, whereas DAP-4IIa-1 consisted mainly of t erminal Araf, 3-linked Glc, and 3,6-branched Gal.