Immunomodulatory activity of polysaccharides isolated from Strongylocentrotus nudus eggs.
Our previous work showed that SEP, a novel glucan isolated from the eggs of sea urchins, Strongylocentrotus nudus, had remarkable anti-tumor activity. To elucidate the mechanism of the anti-tumor activity, the immunomodulatory activity of SEP was investigated. The in vivo experiment results showed that SEP remarkably enhanced spleen and thymus index in S180-bearing mice, and also stimulated ConA-induced splenocyte proliferation. Immunomodulatory activity assay in vitro indicated SEP could significantly enhance the mouse splenocyte proliferation in a dose-dependent manner. According to comitogenic activity tests, SEP showed significant comitogenic activities and adjuvant properties. We also demonstrated that SEP had a unique mode of immunostimulation with regard to its cell-type specificity. In other words, SEP markedly stimulated B and T cell proliferation, however the influence on B cells was greatly weaker than that on T cells. IL-2, TNF-alpha, and IFN-gamma mRNA expression was upregulated after the mouse splenocytes were treated by SEP, indicating that Th1 cell was the primary cellular target affected by SEP on T lymphocyte. SEP enhanced production of nitric oxide (NO), upregulated mRNA expression of inducible nitric oxide synthase (iNOS) in peritoneal macrophages in a dose-dependent manner. In addition, SEP did not show direct toxicity to tumor cells. Consequently, the anti-tumor effect of SEP was related to stimulating host immunity/enhancing the immune system functions, which may mainly result from SEP activating lymphocytes and macrophages and stimulating secretion of some cytokines.
Liu
Chunhui
C
Institute of Biochemical and Biotechnological Drugs, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, PR China. chunhui_l@hotmail.com
Xi
Tao
T
Lin
Qinxiong
Q
Xing
Yingying
Y
Ye
Liang
L
Luo
Xuegang
X
Wang
Fengshan
F
D000276:Adjuvants, Immunologic / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D016207:Cytokines / Q000096:biosynthesis / Q000187:drug effects / Q000276:immunology; D018922:HL-60 Cells; D006367:HeLa Cells; D006801:Humans; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000276:immunology*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000276:immunology; D052247:Nitric Oxide Synthase Type II / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D011112:Polymyxin B / Q000276:immunology / Q000378:metabolism; D011134:Polysaccharides / Q000302:isolation & purification / Q000494:pharmacology*; D013154:Spleen / Q000187:drug effects / Q000276:immunology; D047269:Strongylocentrotus / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
D000276:Adjuvants, Immunologic; D000970:Antineoplastic Agents; D016207:Cytokines; D011134:Polysaccharides; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D011112:Polymyxin B