Received 2002-03-11 Accepted 2002-09-27 Regulatory effect of Ganoderma lucidum polysaccharides on cytotoxic T-lymphocytes induced by dendritic cells in vitro1

dases AIM: To study the regulatory effects of Ganoderma lucidum polysaccharides (Gl-PS) on cytotoxicity and mecha-nism of specific cytotoxic T-lymphocytes (CTL) induced by dendritic cells (DC) in vitro during the stage of antigen presentation. METHODS: Cultured murine bone marrow-derived DC were pulsed with P815 tumor cell lysates and co-incubated with or without various concentrations of Gl-PS (0.8, 3.2, or 12.8 mg/L) at the same time. P815 specific CTL were induced by spleen lymphocytes stimulated with mature DC. Non-adherent cells and culture supernatants were harvested on d 5 for analysis of specific cytotoxicity with lactate dehydrogenase (LDH) activity assay, mRNA expression of IFNg, granzyme B with RT-PCR assay, and protein expression of IFNg, granzyme B with ELISA or Western blot assay, respectively. RESULTS: Three concentrations of Gl-PS promoted LDH activi-ties released into culture supernatants (P<0.01). It also increased mRNA expression of IFNg in CTL (Gl-PS 12.8 mg/L vs RPMI medium 1640, P<0.05) and granzyme B in CTL (P<0.01). Protein production of IFNg in culture supernatants (P<0.05) and protein expression of granzyme B in CTL (Gl-PS 12.8 mg/L vs RPMI medium 1640, P<0.05) were also augmented by Gl-PS. CONCLUSION: Gl-PS is shown to promote the cytotoxicity of specific CTL induced by DC which were pulsed with P815 tumor antigen during the stage of antigen presentation, and the mechanism of cytotoxicity is believed to be going through IFNg and granzyme B pathways