Immunoregulatory effects of a glucogalactan from the root of Panax quinquefolium L.

► A glucogalactan (PPQ) was purified from the roots of Panax quinquefolium. ► Immunoregulatory effects of PPQ was evaluated in Lewis cancer-bearing mouse. ► PPQ could inhibit the growth of lung tumor, and enhance the thymus and spleen indices. ► PPQ significantly improved the level of IFN-γ, IL-10 and IL-2 in tumor-bearing mice.