Augmentation of mitogen-induced interleukin 2 production by oral administration of polysaccharide SPR-901

Induction in the mouse of gene expression of immunomodulating cytokines by mushroom polysaccharide-protein complexes

Two antitumor polysaccharide-protein complexes, PSPC and PSK from mushrooms, were compared for their modulating effect on cytokine and cytokine receptor gene expression. RNA samples were isolated from the splenocytes and peritoneal exudate cells of the untreated or treated mice. Reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze the cytokine gene expression. Nine out of 17 cytokine mRNAs and 5 out of 6 cytokine receptor mRNAs were detected in the splenocytes and peritoneal exudate cells from both untreated and treated mice. However, IL-4 was only detected in the splenocytes while IL-7 and IL-1R(typeI) were only detected in the peritoneal exudate cells. Among the 9 cytokine genes, the expression level of M-CSF was up-regulated in splenocytes and peritoneal exudate cells of the mice by PSPC and PSK. The expression level of TNF-alpha was only up-regulated in the peritoneal exudate cells by PSK, but not by PSPC.

Analysis of effector T cells against the murine syngeneic tumor MethA in mice orally administered antitumor polysaccharide SPR-901

The growth of MethA tumor was significantly inhibited by oral administration of the alpha-glucan SPR-901 in BALB/c (+/+) mice but not in nude mice. Mice treated orally with SPR-901 exhibited an augmentation of antigen-specific resistance against rechallenge with the tumor cells. The tumor-neutralizing activity of regional lymph node cells from MethA-bearing mice against the tumor was augmented by oral administration of SPR-901. The tumor-neutralizing activity of lymph node cells from SPR-901-treated mice mainly appeared in Lyt2+ cells. Furthermore, lymphokine-activated killer activity of these cells was enhanced by administration of SPR-901. The antitumor effect of SPR-901 was abrogated in mice depleted of either L3T4+ or Lyt2+ cells, and in cyclosporin-A-treated mice. These results suggest that Lyt2+ cells are important effector cells in MethA-bearing mice orally administered SPR-901 and that functional exertion of both Lyt2+ and L3T4+ T cells is necessary for the antitumor effect of orally administered SPR-901 in vivo.

Effect of antitumor polysaccharide SPR-901 on antitumor activity in combination with 5-FU

We have examined the effects of the antitumor polysaccharide SPR-901 in combination with 5-fluorouracil (5-FU) on the antitumor activities against mouse syngeneic tumors. SPR-901 was administered p.o. from day 1 to day 10 at the dose rate of 30 mg/kg, and 5-FU was injected i.p. from day 1 to day 5 at the dose rate of 20 mg/kg after BALB/c mice were injected s.c. with 6 x 10(4) cells/mouse of Meth A on day 0. Tumor sizes of mice treated with both SPR-901 and 5-FU were significantly smaller than those from the untreated control group on days 10, 15 and 20. LAK activity of spleen cells from mice treated with both SPR-901 and 5-FU was higher than that from the untreated control group and either the SPR-901 or 5-FU treated group. Flow cytometrical analysis revealed that spleen cells from mice treated with both SPR-901 and 5-FU were much more abundant in both T-cell receptor alpha/beta+ and IL-2 receptor alpha+ T-cells. Furthermore, spleen cells from both the SPR-901- and 5-FU-treated groups exhibited higher growth responses to IL-2 than that from the untreated control group and either of the SPR-901- or 5-FU-treated groups. Therefore, the effects of the antitumor polysaccharide SPR-901 used in combination with 5-FU were augmented as compared with single drug use.