Immunomodulating activity of ginsenoside, Rb1, for antigen-specific immune responses

Kim, Ji Young; Ro, Jai Youl

Abstract

BACKGROUND: It has been reported that Korean Red Ginseng saponins are effective in increasing the synthesis of serum proteins, in cellular proliferation, in producing antibody against sheep red blood cells, and in various cancer. However, there have been no reports yet on the immunomodulating activity of this allergic disease.
OBJECTIVE
This study was conducted to find the immunomodulating activity of a single highly purified ginsenoside, Rb1, by using ovalbumin(OVA) as the antigen. METHOD: BALB/c mice were immunized subcutaneously with OVA containing the alum or ginsenoside, Rb1, twice per 2wk interval. Antigen-specific antibodies and IgG subclasses were determined from serum recovered by cardiac puncture 2 wk after the second immunization by using ELISA method. Antigen-specific cellular proliferation and cytokines were quantified from splenotes obtained from spleens immunized. Cytokine level in cell culture supernatants were determined by ELISA method. NK cell cytotoxicity was generated by co-culture of splenic mononuclear cells against YAC-1 cells as target cells. Hemolytic activity of Rb1 was determined by an in vitro assay using sheep red blood cells.
RESULTS
BALB/c mice immunized with OVA plus Rb1 produced significantly higher titers of antibodies than mice immunized with alum-adsorbed antigen. Rb1 remarkably increased titers in IgG2a and IgG2b subclasses. Antigen-specific proliferative response was more significantly increased with the use of Rb1 than with alum-adsorbed antigen. Rb1 reduced IL-4 production, increased IL-10 production more than alum-adsorbed OVA, but did not affect the IFN-gamma production. High concentration of Rb1 increased the splenic mononuclear cells that were capable of killing YAC-1 cells. Rb1 did not stimulate the production of reaginic antibody (IgE) but alum was able to induce it. Rb1 did not show any hemolytic activity up to 500microgram/ml.
CONCLUSION
The data suggest that the highly purified ginsenoside extracted from Korean Red Ginseng Radix, Rb1, can actively influence the switch of Igs produced by OVA. The data also suggest that Rb1 may be an immunosurveillant in NK cytotoxic activity.