Characterization of an Immune-Enhancing Polysaccharide Fraction Isolated from Heat-Processed Ginseng Derived from Panax ginseng C.A. Meyer

Panax ginseng C.A. Meyer (ginseng) has shown immune-enhancing activity in many studies. The purpose of the present study was to analyze the chemical properties of a polysaccharide fraction (SGP) purified from heat- processed ginseng and to evaluate its immune-enhancing activity using RAW264.7 macrophages. The results showed that SGP increased inducible nitric oxide synthase expression and nitric oxide production in RAW264.7 macrophages. In addition, SGP increased mRNA expression and secretion of interleukin 6 and tumor necrosis factor alpha. Immunoblotting results showed that SGP increased the phosphorylation of mitogen-activated protein kinases (MAPKs) and NF-κB subunit p65 at 500 μg/mL and 1000 μg/mL. Taken together, SGP can activate macrophages through the MAPK and NF-κB signaling pathways, and it may help maintain homeostasis during viral and bacterial infections.

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Tumor Necrosis Factor Alpha- and Inducible Nitric Oxide Synthase-Producing Dendritic Cells Are Rapidly Recruited to the Bladder in Urinary Tract Infection but Are Dispensable for Bacterial Clearance

Infection and Immunity ◽

10.1128/iai.00881-06 ◽

2006 ◽

Vol 74 (11) ◽

pp. 6100-6107 ◽

Cited By ~ 68

Author(s):

Daniel Engel ◽

Ulrich Dobrindt ◽

André Tittel ◽

Petra Peters ◽

Juliane Maurer ◽

...

Keyword(s):

Nitric Oxide ◽

Urinary Tract ◽

Bacterial Infections ◽

Tumor Necrosis ◽

Necrosis Factor Alpha ◽

Tnf Α ◽

Factor Alpha ◽

Oxide Synthase ◽

Necrosis Factor ◽

Inducible Nitric Oxide

ABSTRACT The role of dendritic cells (DC) in urinary tract infections (UTI) is unknown. These cells contribute directly to the innate defense against various viral and bacterial infections. Here, we studied their role in UTI using an experimental model induced by transurethral instillation of the uropathogenic Escherichia coli (UPEC) strain 536 into C57BL/6 mice. While few DC were found in the uninfected bladder, many had been recruited after 24 h, mostly to the submucosa and uroepithelium. They expressed markers of activation and maturation and exhibited the CD11b+ F4/80+ CD8− Gr-1− myeloid subtype. Also, tumor necrosis factor alpha (TNF-α)- and inducible nitric oxide synthase (iNOS)-producing CD11bINT DC (Tip-DC) were detected, which recently were proposed to be critical in the defense against bacterial infections. However, Tip-DC-deficient CCR2−/− mice did not show reduced clearance of UPEC from the infected bladder. Moreover, clearance was also unimpaired in CD11c-DTR mice depleted of all DC by injection of diphtheria toxin. This may be explained by the abundance of granulocytes and of iNOS- and TNF-α-producing non-DC that were able to replace Tip-DC functionality. These findings demonstrate that some of the abundant DC recruited in UTI contributed innate immune effector functions, which were, however, dispensable in the microenvironment of the bladder.

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