The immunostimulating activities of anti-tumor polysaccharide from K1 capsular (polysaccharide) antigen isolated from Klebsiella pneumoniae

Exocellular polysaccharides extracted from mangrove fungus Paecilomyces Lilacinuson present anti-HSV-1 activity in mice

This study examined the anti-HSV-1 activity of EPS extracts isolated from mangrove fungus Paecilomyces Lilacinuson after intraperitoneal administration in mice. Mice were experimentally infected with HSV-1 intracranially and treated intraperitoneally with three different doses of EPS extract (6 g/Kg, 8 g/Kg, and 10 g/Kg) for 7 days. One group of 15 mice was infected with HSV-1 but did not receive any treatment, while another group of 15 mice was mock-infected to remain a control group. Animals were observed twice a day for 14 days after virus infection, searching for clinical signs of weight loss, piloerection, isolation, or retardation movement. Compared with the mock-infected group, mortality was significantly increased (p < 0.05) in the virus-infected group and the groups that received 6 g/Kg and 8 g/Kg EPS extract. Interestingly, no significant differences in mortality were found between the 10 g/Kg EPS extract and the mock-infected group. Mortality in the 10 g/Kg EPS extract group was substantially improved compared with virus-infected(p < 0.05). Additionally, EPS extracts inhibited HSV-1 replication in the mice brain in a dose-dependent manner. Furthermore, the extracts decreased NF-κB protein and mRNA expression and the production of TNF-α in HSV-1-infected mice brain tissue. These effects were also dose-dependent. Our findings suggest that the EPS extract may be a potential candidate for developing an antiviral drug against HSV-1.

Characterization and anti-tumor bioactivity of astragalus polysaccharides by immunomodulation

Astragalus polysaccharide (APS) has attracted growing interests in the field of anti-cancer by direct killing effect and improving immune function. In this study, the structure and composition of APS was determined, following the evaluation of in vitro and in vivo anti-tumor activity of APS targeted macrophages and host immune system based on immunoregulated strategy. The results indicated that APS had no direct cytotoxicity against 4T1 cells, but APS mediated macrophages could significantly inhibit the growth of 4T1 cells by the induction of cell cycle arrest (G2 phase) and cell apoptosis. APS mediated macrophages promoted the apoptosis of 4T1 cells mainly through the mitochondrial apoptosis pathway. The in vivo findings demonstrated that APS could markedly improve the thymus index and spleen index, and restore the structure of the damaged thymus and spleen tissue. APS could significantly enhance the proliferation of spleen lymphocytes and increase phagocytosis of peritoneal macrophages in mice. Furthermore, APS was capable of up-regulating the expression of IL-2, TNF-α and IFN-γ in peripheral blood. APS combined with 5-FU could improve the anti-tumor effect accompanied by the immunosuppressive alleviation of 5-FU on immune system, which may be suitable as an immune adjuvant for chemotherapy.

Antitumor activity and underlying mechanism of Sargassum fusiforme polysaccharides in CNE-bearing mice

This study was designed to investigate the antitumor effects of Sargassum fusiforme polysaccharides (SFPS) on nasopharyngeal carcinoma (NPC) and the underlying mechanism of its effect on splenic lymphocytes. As a result, SFPS significantly inhibited the growth of nasopharyngeal carcinoma CNE in vivo, and remarkably increased the serum cytokines and IgM levels in CNE-bearing mice. Meanwhile, SFPS stimulated the peritoneal macrophages to secrete the cytokines, exerted a stimulatory effect on splenic lymphocytes proliferation, and increased the expression of IgM from splenic lymphocytes. The pretreatment of splenic lymphocytes with special antibodies (anti-TLR4 and anti-TLR2) significantly suppressed the proliferation of splenic lymphocytes and blocked SFPS-induced IgM production. SB203580, a specific inhibitor of p38 MAPK, effectively suppressed SFPS-induced IgM secretion in splenic lymphocytes. Taken together, SFPS has antitumor and immunomodulatory activities in NPC, and its activity is mediated, at least in part, by TLR2/TLR4 receptors and p38 MAPK signaling pathway.

Structure and immunological characterization of the capsular polysaccharide of a pyrogenic liver abscess caused by Klebsiella pneumoniae: activation of macrophages through Toll-like receptor 4

The active components of a primary pyrogenic liver abscess (PLA) Klebsiella pneumoniae in stimulating cytokine expression in macrophages are still unclear. The capsular polysaccharide (CPS) of PLA K. pneumoniae is important in determining clinical manifestations, and we have shown that it consists of repeating units of the trisaccharide (→3)-β-D-Glc-(1→4)-[2,3-(S)-pyruvate]-β-D-GlcA-(1→4)-α-L-Fuc-(1→) and has the unusual feature of extensive pyruvation of glucuronic acid and acetylation of C(2)-OH or C(3)-OH of fucose. We demonstrated that PLA K. pneumoniae CPS induces secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) by macrophages through Toll-like receptor 4 (TLR4) and that this effect was lost when pyruvation and O-acetylation were chemically destroyed. Furthermore, expression of TNF-α and IL-6 in PLA K. pneumoniae CPS-stimulated macrophages was shown to be regulated by the TLR4/ROS/PKC-δ/NF-κB, TLR4/PI3-kinase/AKT/NF-κB, and TLR4/MAPK signaling pathways.

Cardioprotective activity of Cladosiphon okamuranus fucoidan against isoproterenol induced myocardial infarction in rats

Fucoidans, sulfated polysaccharides of brown algae, have attracted steady attention in the last few years as readily accessible biopolymers possessing a wide spectrum of biological activities. In this study, cardioprotective activity of fucoidan extracted from Cladosiphon okamuranus was evaluated in isoproterenol induced myocardial infarction in rats. Male Wistar albino rats (180±25 g) were divided in to four groups of six animals each as follows: Group (1) control, Group (2) isoproterenol alone, Group (3) fucoidan alone and Group (4) fucoidan+isoproterenol. To evaluate the efficacy of fucoidan treatment against isoproterenol induced myocardial damage, biochemical parameters and histopathological studies were carried out. Isoproterenol administration produced severe myocardial damage and high lipid peroxidation level. On the contrary, fucoidan treatment reduced myocardial damage, which has been reflected by improvement in parameters such as creatinine phosphokinase (CPK), lactate dehydrogenase (LDH), alanine transaminase (ALT) and aspartate transaminase (AST). In addition, fucoidan improved the antioxidant defence system in treated animals and considerably reduced the oxidative stress exerted by isoproterenol. The reduction in oxidative stress in Group (4) was evident from the lipid peroxidation and antioxidant activities. Furthermore, the increase in the levels of total cholesterol, triglycerides and low density lipoprotein (LDL) and decrease in the levels of high density lipoprotein (HDL) was significantly reversed in Group (4), when compared with Group (2). The histopathological studies also showed that fucoidan treatment significantly minimized the damage induced by isoproterenol. Thus, fucoidan provide cardioprotection against isoproterenol induced myocardial infarction in rats.

Immunomodulating activity of arabinogalactan and fucoidan in vitro

Many polysaccharides obtained from natural sources are considered to be biological response modifiers and have been shown to enhance various immune responses. Here, we investigated the immunomodulating effects of arabinogalactan (AG) and fucoidan (FU) in vitro. Mouse spleen lymphocytes became cytotoxic to tumor cells after culture with AG and FU at concentrations of 10-100 microg/mL. Also, AG and FU were mitogenic in spleen lymphocytes and peripheral macrophages. Macrophages treated with AG and FU (10-100 microg/mL) exhibited induced tumoricidal activity and increased phagocytosis, lysosomal enzyme activity, and production of nitrite, H2O2, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6. However, AG and FU had little effect on the level of IL-1beta. Thus, the tumoricidal effect of AG- and FU-activated macrophages appeared to be mainly mediated by production of free radicals (NO and H2O2) and cytokines (TNF-alpha and IL-6). These data suggest that AG and FU are activators of lymphocytes and macrophages. This property may contribute to their effectiveness in the immunoprevention of cancer.