Stimulation of humoral and cell mediated immunity by polysaccharide from mushroom Phellinus linteus

Polysaccharide was purified from mycelial culture of Phellinus linteus (PL) and its effect on immunocompetence of normal splenocytes was observed. Overall in vitro and in vivo immune function was enhanced by addition of PL into culture of mouse spleen lymphocyte and I.p. injection into mouse, while β-glucans and other polysaccharides only raised the level of T lymphocyte-mediated immunity. PL stimulated immune functions of T lymphocytes, such as proliferation of T lymphocyte induced by mixed lymphocyte reaction and cytotoxicity of cytotoxic T cells responding to alloantigen. Nonspecific immune functions mediated by natural killer cells and macrophages were increased by treatment of PL in vitro and in vitro. PL also stimulated humoral immune function positively, such as T-dependent and T-independent primary antibody responses, and acted as a polyclonal activator on B cell. PL exhibited a wider range of immunostimulation and antitumor activity than other polysaccharides isolated from Basidiomycetes.