Antitumor immunostimulatory activity of polysaccharides from Panax japonicus C. A. Mey: Roles of their effects on CD4+ T cells and tumor associated macrophages.

In this study, chemical properties of polysaccharides from rhizomes of Panax japonicus C. A. Mey (PSPJ) were investigated and the antitumor immunostimulatory activity of PSPJ was assessed in mice bearing H22 hepatoma cells. Chemical properties of PSPJ were determined by GC, FT-IR, 1H NMR and 13C NMR analysis. Furthermore, we showed that PSPJ repressed H22 tumor growth in vivo with undetectable toxic effects on tumor-bearing mice. PSPJ upregulated host thymus/spleen indexes and ConA/LPS-induced splenocyte proliferation. Cytotoxic activities of natural killer and CD8+ T cells against H22 hepatoma cells were also elevated. Tumor transplantation led to substantial apoptosis of CD4+ T cells and dysregulation of the cytokine profile secreted by CD4+ T cells. These abnormalities were alleviated by PSPJ in a dose-dependent manner. In tumor-associated macrophages (TAMs), PSPJ reduced the production of immunosuppressive factors such as TGF-β, IL-10 and PEG2. In addition, M2-like polarization of TAMs was also considerably declined in response to PSPJ. Our findings clearly demonstrated the antitumor immunostimulatory activity of PSPJ and supported considering PSPJ as an adjuvant reagent in clinical treatment of malignant diseases.