Abstract
Ganoderma formosanum is a native species of Ganoderma isolated in Taiwan, and our previous studies showed that a polysaccharide fraction, PS-F2, purified from the submerged culture fluid of G. formosanum ATCC 76538 exhibited immunostimulatory and antitumor property. In the current study, we investigated the immunomodulatory and antitumor effects of PS-F2 from a UV-mutated G. formosanum variant NTU-1, which produced higher yields of PS-F2 than the original strain. Oral administration of PS-F2 effectively suppressed the growth of colon 26 (CT-26) carcinoma and splenomegaly in tumor-bearing mice without adversely affecting the animals’ health. We found that PS-F2 treatment resulted in augmented cytotoxic T lymphocyte (CTL) while significantly reducing the accumulation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and regulatory T (Treg) cells in the spleen. In the tumor, PS-F2 treatment markedly enhanced CTL and Th1 responses, whereas it reduced the accumulation of tumor-associated macrophages (TAMs). Collectively, our data demonstrate that oral treatment of PS-F2 from G. formosanum NTU-1 in CT26 tumor-bearing mice activates antitumor immune responses and reduces the accumulation of immunosuppressive cells in the spleen and the tumor, leading to delayed tumor progression.
Competing Interest Statement
The authors have declared no competing interest.