A Polysaccharide Carrier to Effectively Deliver Native Phosphodiester CpG DNA to Antigen-Presenting Cells

Oligodeoxynucleotides containing unmethylated CpG sequences (CpG DNAs) activate the vertebrate innate immune system via toll-like receptor 9 (TLR-9). Although CpG DNA is a promising immunotherapeutic agent, its short circulation time in biological fluids due to nuclease is the major drawback. This paper proposes that a natural polysaccharide called schizophyllan (SPG) can be used as an effective CpG DNA carrier because SPG can complex with CpG DNA and the resultant complex shows the nuclease resistance of the bound DNA. In order to increase cellular uptake in vitro, we chemically attached spermine, cholesterol, arginine octamer, or RGD peptide to SPG. The complexes made of the chemically modified SPG and CpG DNA having a phosphorothioate (PS) or phosphodiester (PO) backbone led to increased secretion of cytokines of about 4- to 15-fold, compared with the uncomplexed dose. Furthermore, when PO CpG DNA was complexed with unmodified SPG, the IL-12 level increased by almost 3- to 11-fold compared with the naked dose. The PO CpG DNA/unmodified SPG complex data suggested that unmodified SPG might effectively deliver PO in vivo due to the electrically neutral nature of unmodified SPG. When the complexed CpG DNAs were injected intraperitoneally, a large amount of IL-12 production was observed compared with the uncomplexed material. Both in vivo and vitro assays indicated that the SPG complex may be of use for CpG DNA therapy.

A Polysaccharide Carrier for Immunostimulatory CpG DNAs To Enhance Cytokine Secretion‖

A beta-(1 --> 3)-d-glucan schizophyllan (SPG) forms a stoichiometric complex with some polynucleotides. This communication describes our attempt to apply the SPG complex to deliver CpG DNA to endosomes to enhance cytokine secretion. To increase cellular uptake, we introduced spermine, arginine-glycine-aspartic acid tripeptide, octaarginine, or cholesterol to the SPG side chain. The chemically modified SPG showed essentially no cytotoxicity. When CpG DNA complex made therefrom was exposed to macrophages, dramatic enhancement in the cytokine secretion was observed. It increased 5-10 times from the naked dose and 100 times from the background. This performance promises that SPG can be an excellent carrier for CpG DNA.

Chemically modified polysaccharide schizophyllan for antisense oligonucleotides delivery to enhance the cellular uptake efficiency

Schizophyllan is a natural beta-(1-->3)-D-glucan existing as a triple helix in water and as a single chain in dimethylsulfoxide (DMSO), respectively. As we already reported, when some homo-phosphodiester polynucleotide (for example, poly(dA) or poly(C)) is added to the schizophyllan/DMSO solution and subsequently DMSO is exchanged for water, the single chain of schizophyllan forms a complex with the polynucleotide. Furthermore, we have already demonstrated that one of the potential applications of this novel complex is an antisense-oligonucleotide (AS ODN) carrier. This work describes a versatile and universal modification technique which enables us to introduce various functional groups only to the side chain of schizophyllan. This technique consists of periodate oxidation of the glucose side chain (it does not react with the main chain because of the absence of the 1,2-diol group in beta-(1-->3)-glucan) and subsequent introduction of the functional groups into the formyl terminate. In the present work, the introduced functional groups were spermine, octa-arginine (R8), arginine-glycine-aspartic acid tripeptide (RGD) and some amino or alpha-amino acid compounds. Using these compounds, we made the complexes and carried out an in vitro antisense assay for them, administrating a phosphorothioate AS ODN to the melanoma A375 or leukemia HL-60 cell lines to depress their c-myb mRNA. When we used the R8 or RGD modified schizophyllan as the antisense carrier, the antisense effect was most enhanced among others. Their superiority can be ascribed to enhancement of endocytosis due to these functional peptides. Furthermore, the cytotoxicity for these two modified schizophyllans was negligibly as small as the natural (unmodified) schizophyllan. One of the peculiar features of our system is that the complex (i.e., carrier+AS ODN) is charged negatively in total, which is different from the conventional systems. The present work has thus clarified that schizophyllan can act as a new potential candidate for AS ODN carriers.

Immunotoxicity of soluble beta-glucans induced by indomethacin treatment

(1 --> 3)-Beta-D-Glucan (beta-glucan) is a biological response modifier that regulates host immune response. However, the side effects of this drug have not been extensively examined. In this study, we found that the combination of a beta-glucan and a nonsteroidal anti-inflammatory drug, indomethacin, induced lethal toxicity in mice. Lethal toxicity of orally administered indomethacin (multiple administration to ICR mice; once a day for 2 weeks) was 0/8 (2.5 mg kg(-1)) and 5/8 (5 mg kg(-1)) (death/total) over 2 weeks. The toxicity was enhanced to 3/8 and 8/8 in mice treated with a clinical beta-glucan preparation, sonifilan (250 microg/mouse, single i.p. administration on day 0). A similar effect was observed for other beta-glucans, including SSG, grifolan, zymosan A and zymocel. Enhanced lethal toxicity resulted from a single p.o. administration of indomethacin on day 5 to day 9 after multiple beta-glucans administration. Interferon-gamma, interleukin-6 and colony stimulating factor concentrations in sera of indomethacin/beta-glucan-treated mice were significantly elevated. These results strongly suggest that indomethacin/beta-glucan treatment induces lethality in mice by maladjusting the cytokine network.

[Effect of 5'-DFUR used concurrently in radiotherapy and immunotherapy uterine cervical cancer--pilot study. Study of 5'-DFUR for Uterine Cervical Cancer]

We conducted a preliminary controlled study in order to evaluate 5'-DFUR dose dependency in efficacy and safety in combination therapy of radiotherapy, 5'-DFUR and SPG for patients with uterine cervical cancer, which was regarded as suitable for cases of radiotherapy. The patients were randomly allocated into group A (5'-DFUR 600 mg/body/day) and group B (5'-DFUR 800 mg/body/day), who underwent radiotherapy with simultaneous administration of 5'-DFUR and SPG (20 mg twice/week or 40 mg/ week). Those enrolled were 33 patients in stage II, III or IV a with histologically diagnosed primary squamous cell carcinoma of uterine cervix. CR was shown in 19, PR in 7, NC in 1, and PD in 2 out of 29 efficacy-evaluable cases, so the overall response rate was 89.7% (26/29, 95% CI 72.7%-97.8%). Regarding safety, some side effects were observed in 26 out of 33 safety-evaluable cases (81.3%, 95%, CI 63.6%-92.8%), but no serious cases. No significant difference in efficacy and safety was observed between the two treatment groups. These results suggested that the combination therapy of radiotherapy, 5'-DFUR and SPG might be one of the therapies whose effectiveness must be confirmed for advanced squamous cell carcinoma of uterine cervix. To confirm dose dependency of 5'-DFUR, it seems further consideration with more patients is needed.

Intratumoral administration of sizofiran activates Langerhans cell and T-cell infiltration in cervical cancer

In order to ascertain a correlation between infiltration of Langerhans cells (LCs) or T-cells in tumor tissues and the intratumoral administration of a biological response modifier, Sizofiran (SPG) was analyzed in cancer of the uterine cervix. Cancer specimens of 45 patients with stage II-III invasive cervical cancers were analyzed. SPG was administered to the cervical tumor at high and low concentrations (Strong SPG and weak SPG) as well as by intramuscular injection twice a week. LC and T-cell infiltrations to tumor tissues of the uterine cervix were studied immunohistochemically and electron microscopically. Of 10 patients with systemic but no local immunization, 1 (10.0%) showed an increase in LC infiltration and 2 (20.0%) showed a decrease. Of 15 patients with strong SPG immunization, 2 (13%) showed an increase and 5 (33%) showed a decrease. In contrast, of 20 patients with weak SPG immunization, the incidence of increase in LC infiltration was 55% (11 patients), significantly greater than the above-mentioned groups and none showed a decrease. Of the 20 patients with weak SPG administration, 3 (15%) showed T-cell infiltration before SPG administration, and 12 (60%) showed an increase in T-cell infiltration after SPG was given. Up on electron microscopy, Birbeck granules in the cytoplasm of LC significantly increased after SPG immunization, indicating activation of LC. In conclusion, the present study suggested that the LC and T-cell infiltrations in cancer tissues were augmented by intratumoral SPG administration at a certain concentration. Intratumoral administration of SPG may be applied to improve the prognosis after multidisciplinary treatment of advanced cervical cancer.

[Combined effects of sizofiran and rG-CSF on myelosuppression in cancer chemotherapy]

A combination of the antitumor polysaccharide Sizofiran and rG-CSF was investigated for its effects on peripheral blood counts in ovarian cancer patients undergoing chemotherapy. We performed the analysis by using variations in peripheral blood counts and the duration of treatment as variables. In the analysis, effects on decreases in both neutrophils and platelets and their recoveries could be assessed. As a result, the decrease in neutrophils was inhibited and its recovery was promoted, suggesting that the combined use of the drugs may be useful for myelosuppression by chemotherapy for ovarian cancer.

Augmentation of antitumor effect by combined administration with interleukin-2 and sizofiran, a single glucan, on murine EL-4 lymphoma

The antitumor effect of the combined administration with recombinant human interleukin-2 (rIL-2) and sizofiran (SPG), a single glucan of Shizophyllum commune Fries, was studied in vivo in C57BL/6 mice intraperitoneally inoculated with EL-4 lymphoma. The effect was evaluated by a) comparing the survival time of the mice, b) analysis of the intraperitoneal cell population in Giemsa-stained specimens, c) surface marker analysis of peritoneal exudative cells with flow cytometry, d) cytotoxic assay of cells against EL-4 and Yac-1 lymphoma, and e) elimination of some cell populations by monoclonal antibodies, to identify the antitumor-effector cells showing cytotoxic activity. The survival of mice given both rIL-2 and SPG was significantly longer than the control mice or those given SPG alone or rIL-2 alone. It was demonstrated that the administration of SPG and/or rIL-2 to the EL-4 lymphoma-bearing mice activated immune-response cells in the peritoneal cavity such as T lymphocytes, NK cells, or macrophages, which might be effective in reducing lymphoma cells. The combination of rIL-2 and SPG administration appears to activate the antitumor-immune response at the tumor site more effectively than when either agent was administered alone.

Inhibitory effect of metastasis by combined administration with interleukin-2 and sizofiran, a single glucan--immunohistochemical study

Innovations in methods of combined administration with other BRM or chemotherapeutic drugs have been discussed. We have reported that combined administration with recombinant interleukin-2 (rIL-2) and sizofiran (SPG) is effective in prolonging survival time of C57BL/6 mice intraperitoneally inoculated with EL-4 lymphoma. The immunomechanisms of the combined administration were clarified investigating the intraperitoneal cell population in the primary tumor site, especially the tumor infiltrating lymphocyte (TIL) quantitatively. In the present study, to clarify the antitumor effects of combined administration with rIL-2 and SPG on the metastatic sites, the immunomechanisms of the suppressive effects of combined administration on the metastasis were studied in EL-4 lymphoma cells intraperitoneally transplanted to mice. Inasmuch as EL-4 lymphoma shows rapid hepatosplenic metastasis, we studied the metastatic foci in the liver and the spleen semiquantitatively in investigating the histopathological and immunohistochemical findings of the metastatic foci, especially the TIL. The metastatic foci were stained by hematoxylin-eosin (HE) and monoclonal antibodies (L3T4, Lyt2, asialo GM1, Mac-1, and Ia). The combined administration resulted in: 1) fewer infiltrating tumor cells, 2) more lymphocytic infiltration, and 3) more antitumor effector cells (cytotoxic T cells: Lyt2 and natural killer cells: asialo GM1), macrophages (Mac-1), helper T cells (L3T4), and cells with MHC-class-II antigen (Ia) than did administration of rIL-2 alone or SPG alone, or no administration of these two at all. Combined administration with rIL-2 and SPG appears to activate antitumor-immune response at the metastatic site more effectively than when either agent is administered alone.

Comparison of the blood clearance of triple- and single-helical schizophyllan in mice

(1-->3)-beta-D-Glucans exhibit a variety of biological and immunopharmacological activities, and the degree of these activities depends on the nature of the individual glucans e.q. molecular weight, degree of branching and conformation. Based on the generally accepted evidence that the conformation of Sonifilan (SPG) used clinically is a triple helix, we prepared alkali-denatured SPG (SPG-OH) as a single helix conformer. In this report, we measured the concentration of beta-glucan administered to mice by using a beta-glucan-specific reagent prepared from limulus amebocyte lysate (Gluspecy [G test], Seikagaku Corporation, Tokyo) and discuss the blood clearance of SPG and SPG-OH following intraperitoneal (i.p.) or intravenous (i.v.) administration. Comparing the clearance of SPG-OH from the blood with that of SPG, SPG-OH was removed faster than SPG following both i.p. and i.v. administration. This strongly suggests that the clearance of beta-glucans is dependent on their conformation.

An improved sandwich ELISA method for the determination of immunoreactive schizophyllan (SPG)

As it is important to determine the optimal serum concentration of schizophyllan (SPG) when it is used as an anti-cancer drug, we devised a solid-phase ELISA. We also developed a sandwich ELISA using murine anti-SPG monoclonal antibody as the first antibody and rabbit anti-SPG serum as the second antibody in order to improve the detection sensitivity. This assay was able to determine SPG concentrations over 1.0 ng/ml and the absorbance at 490 nm was directly proportional to the SPG concentration. SPG in rabbit serum, obtained after intravenous and intramuscular injection (SPG; 10 mg/kg), was determined by this sandwich ELISA. Furthermore, the sensitivity of this ELISA method was compared with that of the Limulus test. The Limulus test is able to detect SPG in physiological saline (pH 6.3) at concentrations greater than 1.0 microgram/ml, but the sensitivity increased when SPG was dissolved in alkaline solution (pH 12.0), enabling SPG to be measured almost down to 1.0 ng/ml. These data suggest that our sandwich ELISA may be used for the measurement of SPG in blood or tissue.

[Immunotherapy of malignant lymphoma with interleukin-2 and sizofiran--a basic study on EL-4 lymphoma-transplanted mice]

The anti-tumor effects of recombinant human interleukin-2 (rIL-2) and sizofiran (SPG) were evaluated individually and in combination in C57BL/6 mice intraperitoneally inoculated with EL-4 lymphoma. The anti-tumor effects were evaluated by analysis of the intraperitoneal cell population in Giemsa-stained specimens, surface marker analysis of peritoneal exudative cells with flow cytometry, cytotoxic assay of cells against autologous tumor and Yac-1 lymphoma and a negative selection method, to identify the anti-tumor effector cells showing cytotoxic activity. The administration of SPG and/or rIL-2 reduced the lymphoma cells and proliferating lymphocytes, resulting in a decreased tumor/lymphocyte ratio in the order:control mice > SPG-treated mice > rIL-2-treated mice > rIL-2 plus SPG-treated mice. On day 5 after tumor inoculation, elevations in the number of L3T4+, Lyt2+, asialo GM1+ or Mac-1+ were demonstrated in the order:control mice < SPG-treated mice < rIL-2-treated mice < rIL -2 plus SPG-treated mice. The cytotoxic activity of peritoneal exudative cells against autologous tumor and the NK (natural killer) activity were increased in the same order. The anti-tumor effector cells which showed cytotoxic activity against autologous tumor cells were cytotoxic T lymphocytes, NK cells and cytotoxic macrophages. In the mice treated with SPG and rIL-2 plus SPG, especially, cytotoxic macrophages were shown to be the main anti-tumor effector cells. On day 10 after the inoculation, both a marked reduction in Lyt2+ lymphocytes and an elevation of L3T4+ lymphocytes were observed in all groups of mice. NK cells and cytotoxic macrophages were thought to be the main effector cells against autologous tumor, but their cytotoxic activities were lower than those examined on day 5. It was demonstrated that the administration of SPG and/or rIL-2 to the EL-4 lymphoma-bearing mice activated immune response cells in the peritoneal cavity such as T lymphocytes, NK cells or macrophages, which caused a reduction in lymphoma cells. The combination rIL-2 and SPG therapy was shown to activate the anti-tumor immune response at the tumor site more effectively than when either agent was administered alone.

Clinical evaluation of sizofilan as assistant immunotherapy in treatment of head and neck cancer

Sizofilan (SPG), a simple glucan produced in a culture medium by Schizophyllum commune Feries, was used as an assistant immunotherapy in 15 patients with head and neck cancer. The cumulative 5-year survival rate was 86.7% in the SPG-treated group and 73.4% in the control group. Immunological parameters showed that the SPG group quickly recovered the cellular immunity damaged by radiation, chemotherapy and surgical procedure. SPG was found to be effective as an assistant immunotherapeutic agent in the treatment of head and neck.

[Two cases of cancer with bone metastases treated with local therapy]

Two cases with osteolytic bone metastases from cervical cancer and esophageal cancer treated by local therapy were reported. The first case is a 53-year-old female with bone metastases of left ischium developed 1 year after hysterectomy. She was treated by intratumor injection of sizofiran (SPG) 20 mg/w and radiation therapy. After 4 weeks, ischias pain decreased and bone lesion showed remarkable calcification (PR) 8th months later. The second case is a 58-year-old male with bone metastases of the left tibia and fibula developed 1 year after surgery. He was treated by intratumor injection of SPG 20 mg/w x 4 and OK-432 1.0 KE/w x 8 after radiation therapy. After 4 weeks, pain and swelling of left leg decreased and bone lesions showed remarkable calcification (PR) three months later. We suggest that intratumor injection of SPG and OK-432 with radiation therapy was effective for osteolytic bone metastases.

[Concomitant intraperitoneal therapy with the antitumor polysaccharide Sizofiran and rG-CSF for ovarian cancer]

The concomitant administration of Sizofiran (a macrophage activator) and rG-CSF (which promotes neutrophil proliferation and activation) caused marked activation of intraperitoneal antitumor immunity. It promoted the induction of IL-2 receptor expression as well as the proliferation and activation of neutrophils, and also caused an increase in LAK and NK activity, which resulted in a clinical antitumor effect. Therefore, this concomitant regimen was found to be useful as maintenance therapy for ovarian cancer.

Interferon-alpha, interferon-gamma and sizofiran in the adjuvant therapy in ovarian cancer--a preliminary trial

The study included 24 cases of negative second-look laparotomy (SLL) after operation on ovarian cancer. 12 cases were treated with sizofiran and recombinant interferon-gamma before and after SLL and then with human lymphoblastoid interferon-alpha. The remaining 12 cases (controls) were followed up without any drug therapy after SLL. There were no recurrences in the treated group, but in 3 cases of the control group. Also significant difference in survival was noted in the treated group.

[Maintenance of the activation of peritoneal macrophage in patients with ovarian cancer by the repeated administration of sizofiran and interferon gamma]

Four patients with ovarian cancer were treated with a 20mg injection of sizofiran, a MW 450,000 beta-1,3-glucan, intramuscularly one day before and 4,7,11,14,18 and 21 days after second look laparotomy and with the administration of 2 million units of interferon gamma intraperitoneally at 0,4,7,11,14,18 and 21 days after second look laparotomy. Peritoneal macrophages were obtained from the patients by peritoneal washing with saline through an indwelled tube. The number of macrophages was increased to about 30 times after the treatment. The concentrations of interleukin 1, interferon gamma, tumor necrosis factor and prostaglandin E2 in the media of 24-hour cultured macrophage with 10 micrograms/ml of LPS were also increased throughout the treatment. These data suggest that the every 3 to 4 day treatment with sizofiran and interferon gamma maintained the activation of peritoneal macrophages which might lead to retention of the antitumor activity in patients with ovarian cancer.

[Sizofiran and recombinant interferon gamma stimulate peritoneal macrophages obtained from patients with gynecologic malignancies--increased secretion of tumor necrosis factor, IL-1 and interferon-gamma]

TNF, IL-1, IFN-gamma and PGE2 secretion of peritoneal macrophage obtained by peritoneal washing at the first day after laparotomy from 19 patients with cervical cancer and 19 with ovarian cancer, who were treated with sizofiran (SPG) intramuscularly before laparotomy or with recombinant interferon gamma (rIFN) intraperitoneally at the day of laparotomy, were studied. Treatment with SPG and rIFN significantly increased the number and secretion of TNF, IL-1 and IFN-gamma (p less than 0.05) but not that of PGE2. A high correlation between secretion of TNF and IFN-gamma (r = 0.99, p less than 0.01) was observed. These data suggest that potent tumoricidal activity of peritoneal macrophage obtained from the patients with gynecological malignancies could be expected by the treatment with SPG and rIFN due to the increased secretion of TNF, IFN-gamma and IL-1 and inhibition of increased secretion of PGE2.

[Studies on metabolism and disposition of sizofiran (SPG), an anti-tumor polysaccharide. II. Effects on hepatic drug-metabolizing enzyme system in rats]

The effect of a single or multiple administration of sizofiran (SPG), an anti-tumor polysaccharide, on a hepatic drug-metabolizing enzyme system was studied in rats. When SPG was given intravenously at a single dose of 0.5 or 10 mg/kg, no alteration was observed in activities of aminopyrine (AP) N-demethylase and aniline hydroxylase, and in cytochrome P-450 (P-450) content in the livers of rats 48 h after dosing. However, only AP demethylase activity decreased by 34% after the administration of 200 mg/kg. Similarly, no change in the hepatic enzyme activities and P-450 content was observed for up to 180 d after a single dose of 10 mg/kg. Subcutaneous treatment of animals with either 10 or 40 mg/kg dose for 3 and 6 months resulted in no alteration in the enzyme activities and P-450 content. These results may indicate that the therapeutically effective dose of SPG has no effect on a hepatic drug-metabolizing enzyme system in rats.

[Effect of sizofiran or recombinant interferon gamma on the activation of human peritoneal macrophage function; an approach for the prophylaxis of intraperitoneal recurrence of ovarian cancer]

Sixty-two patients with gynecological disease, who were treated with sizofiran (SPG) intramuscularly before laparotomy or with recombinant interferon gamma (IFN) intraperitoneally on the day of the laparotomy, were studied to investigate the change on the number and function of peritoneal macrophages (PM) obtained by peritoneal washing on the day and on the 1st and 4th days after the laparotomy. SPG significantly increased the number of PM by the 1st day, and IFN by the 4th day (p less than 0.05). However, IL-1 and IFN-gamma secretion by PM were not activated by SPG or IFN treatment, respectively. When patients were treated with these two agents simultaneously, the number of PM was significantly increased by both the 1st and the 4th day (p less than 0.05), and IL-1 and IFN-gamma secretion by PM were also significantly activated by the 1st day (p less than 0.05). These data suggest that SPG and IFN had a synergistic effect on increasing the number of PM and on activating the secretion of cytokines by PM, and that the priming with SPG played an important role in the activation of PM function by IFN.

[A case report of patient with advanced stomach carcinoma of linitis plastica type responding to multi-immunotherapy and chemotherapy]

Multiple-drug (OK-432, PSK and SPG) immunotherapy and chemotherapy provided remission of symptoms for 36 months in a patient aged 21 years suffering scirrhous gastric carcinoma associated with carcinomatous peritonitis in which direct infiltration to the pancreas, retroperitoneum and the left colon was observed. A remarkable improvement with time was observed by endoscopic and roentgenographic observation, and a substantial improvement was also observed in the NK-cell ratios of lymphocyte subsets of the OKT series in relation to immunologic parameters. A tumor necrosis factor [TNF]-like substance was thought to have been induced by multiimmunotherapy in this case.

[A long-term survivor of primary hepatoma--a case suggesting the superiority of a multi-drug (OK-432, SPG, PSK) over mono-drug immunotherapy]

The studied patient (70 years old, male) had primary hepatoma with rupture of the liver. We resected his left lobe partially and were able to save him. Since a residual tumor was found after surgery, we injected a total of 30 mg of MMC into the SCA 3 times. Under continuous administration of OK-432, the patient survived for 3 years and 6 months in remission. Because the tumor grew gradually, we started a multi-drug immunotherapy (OK-432 5 KE/2 W/intradermal, PSK/3.0 g/day/P.O., SPG/20 mg/2 W/I. M.) which we have advocated. In 6 months the tumor regressed to 1/3 of its original size. The patient is currently in good condition 4 years and 7 months after the operation. This case demonstrated the superiority of multi-drug immunotherapy over single-drug immunotherapy.

[Clinical evaluation of schizophyllan (SPG) in advanced gastric cancer (the second report)--a randomized controlled study]

We reported previously that Schizophyllan (SPG) combined with MMC + 5-FU (MF regimen) or Tegafur (F regimen) had a significant life-prolonging effect over chemotherapeutic regimens in patients with inoperable and recurrent gastric cancer in a randomized controlled study. In the present paper, we have further investigated the effect of SPG on life-span followed-up for more than 2 years. A significant life-prolonging effect of SPG was reconfirmed in patients given either the MF regimen (154 patients) or the F regimen (213 patients). Thus, SPG combined with chemotherapeutics has proved to be useful for treating patients with inoperable and recurrent gastric cancer, resulting in a significant prolongation of life-span without serious side effects despite having no influence on tumor size.

[Immunochemotherapy with tegafur and schizophyllan for stomach cancer--report of 2 cases]

Two cases of gastric cancer were treated with immunochemotherapy using Tegafur and Schizophyllan. In one case, a marked reduction in the size of metastatic liver tumor and disappearance of most subjective symptoms were observed. The response continued even 8 months after the initial treatment. In the other case, no marked symptoms except occasional dysphagis have been noted for 2 years and 2 months since diagnosis, although the primary tumor size has remained unchanged. Thus, it is presumed that the combined immunochemotherapy regimen may be useful in the treatment of advanced gastric cancer.

[Clinical evaluation of schizophyllan (SPG) in advanced gastric cancer--a randomized comparative study by an envelope method]

To clarify the clinical efficacy of SPG, a beta-1, 3 glucan extracted from cultured Schizophyllum commune Fries, a randomized comparative study was performed in combination with mitomycin C+5-fluorouracil (MF protocol) or tegafur (F protocol). A total of 514 cases with inoperable or recurrent gastric cancer were randomly allocated to either the SPG group or the control group, 367 of which were finally assessed for clinical efficacy. SPG was intramuscularly given at a dose of 20 mg twice a week or 40 mg once a week. Significant prolongation of life span was confirmed in the SPG group (MF protocol: p less than 0.01, F protocol: p less than 0.05), although the combination of SPG did not demonstrate a remarkable antitumor effect in both MF and F protocols. Among immune response parameters tested, the positive reactions in the PHA skin test were maintained in the SPG group and decreases in lymphocyte counts were inhibited by SPG in the MF protocol. Side effects associated with SPG therapy were noted in 6 of 258 cases treated with SPG. From these results, it is indicated that the combination of SPG and the chemotherapeutic agents may be useful in treating patients with inoperable or recurrent gastric cancer.

[Clinical evaluation of SPG (schizophyllan) as a therapeutic adjuvant after surgery of gastric cancer--controlled study by an envelope method]

SPG, a beta-1, 3 glucan extracted from cultured Schizophyllum commune Fries, was clinically evaluated for its efficacy in adjuvant immunochemotherapy for postoperative gastric cancer by the SPG cooperative study group comprising 43 hospitals. On the day of operation and the next day, patients were given intravenously 0.4 mg and 0.2 mg/kg of mitomycin C, respectively. Subsequently, they were randomly allocated to either the SPG group or control group. From the 10th to 20th postoperative days, the SPG group was intramuscularly given SPG at a dose of 20 mg twice a week or 40 mg once a week in combination with tegafur, while the control group was given only tegafur. Significant prolongation of life span of the SPG group was confirmed in Stage III. Minor side effects due to SPG were noted in 2.6% (5/190).

[Experimental study on immunochemotherapy using schizophyllan]

Immunochemotherapy with schizophyllan (SPG) combined with chemotherapeutic agents was evaluated in two syngeneic tumor-C3H/He mouse systems. The administration of SPG alone caused a significant growth inhibition of MM 46 mammary carcinoma, the highest therapeutic effect being obtained by SPG given at the advanced stage of tumors. When combined with neocarzinostatin given 7-times every other day the simultaneous administration of SPG produced an optimal response to that therapy. In X-5563 plasmacytoma, SPG alone was ineffective. However, when combined with mitomycin C given with 1 to 5-days interval, the concurrent administration of SPG prolonged significantly the life-span of the tumor-bearing mice. These results indicated that the simultaneous administration of SPG and antitumor drugs may be a useful application method for immunochemotherapy of experimental tumors.

[Effect of schizophyllan on delayed hypersensitivity in the mouse (author's transl)]

The delayed cutaneous hypersensitivity test with picryl chloride was used to demonstrate the effect of sonicated schizophyllan (SPG-S) on cellular immunity in mice. The increase of ear thickness in mice treated with SPG-S (0.5 approximately 10.0 mg/kg) 24 hours before the sensitization with picryl chloride proved to be significantly larger than that in untreated mice on testing with picryl chloride at 7 days following sensitization. Mice were intramuscularly injected with SPG-S (5.0 mg/kg) on -48, -24, 0, +24 or +48 hours of sensitization. Remarkable stimulating effect of SPG-S on the delayed hypersensitivity was recognized in all groups of mice, being somewhat lower in the group treated with SPG-S 48 hours after the sensitization. Stimulating effects of lipopolysaccharide, concanavalin A, pokeweed mitogen and SPG-S on the delayed hypersensitivity were compared. The effect of SPG-S was similar to that of concanavalin A, a nonspecific stimulant for T cells.

[Influence of schizophyllan, streptomycin and rifampicin on histopathological changes in mice infected with tubercle bacilli (author's transl)]

Experimental tuberculosis in mice infected with streptomycin-resistant Mycobacterium tuberculosis SCHACHT strain was treated with streptomycin or rifampicin alone and in combination with schizophyllan. The histopathogical tests of various organs of the treated mice were carried out. 1) In the group of mice treated with streptomycin alone, the moderate focal proliferation of RE cells were seen at the beginning of infection. However, durable activation of RE cells and the prolongation of life-span could not be recognized as compared with control animals. 2) The treatment with streptomycin-schizophyllan combination appeared to be somewhat more effective than schizophyllan alone, the phagocytic capacity being more strongly stimulated. 3) In the group treated with rifampicin alone, the therapeutic effect could be exhibited by the direct antibacterial action of rifampicin, but the activation of RE cells was slight. When rifampicin was discontinued, the growth of tubercle bacilli was rapidly resumed, and the durable therapeutic effect seemed not to be expected. Degeneration of hepatic cells tended to develop. 4) In the group treated with rifampicin-schizophyllan combination, the antibacterial effect of rifampicin appeared to be potentiated by the strong activation of RE cells by schizophyllan, showing the durable therapeutic effects.