We have isolated a novel type of natural tumoricidal product from the basidiomycete strain, Agaricus blazei Murill. Using the double-grafted tumor system in Balb/c mice, treatment of the primary tumor with an acid-treated fraction (ATF) obtained from the fruit bodies resulted in infiltration of the distant tumor by natural killer (NK) cells with marked tumoricidal activity. As shown by electrophoresis and DNA fragmentation assay, the ATF also directly inhibited tumor cell growth in vitro by inducing apoptotic processing; this apoptotic effect was also demonstrated by increased expression of the Apo2.7 antigen on the mitochondrial membranes of tumor cells, as shown by flow-cytometric analysis. The ATF had no effect on normal mouse splenic or interleukin-2-treated splenic mononuclear cells, indicating that it is selectively cytotoxic for the tumor cells. Cell-cycle analysis demonstrated that ATF induced the loss of S phase in MethA tumor cells, but did not affect normal splenic mononuclear cells, which were mainly in the G0G1 phase. Various chromatofocussing purification steps and NMR analysis showed the tumoricidal activity to be chiefly present in fractions containing (1-->4)-alpha-D-glucan and (1-->6)-beta-D-glucan, present in a ratio of approximately 1:2 in the ATF (molecular mass 170 kDa), while the final purified fraction, HM3-G (molecular mass 380 kDa), with the highest tumoricidal activity, consisted of more than 90% glucose, the main component being (1-->4)-alpha-D-glucan with (1-->6)-beta branching, in the ratio of approximately 4:1.

Licorice extract is an herbal drug which has long been used as a demulcent and elixir in Chinese medicine. One of the main active components of licorice extract is glycyrrhizin (GL), a kind of saponin. The biological effects of GL and its aglycone, glycyrrhetinic acid (GA), have been extensively studied. Their anti-inflammatory (5), anti-ulcerous (3), and antiviral (14) effects have been reported from 1948 (15) to 1979 (14). Moreover, a preparation of GL combined with glycine and cysteine (SNMC), has been widely and successfully used in Japan as an antihepatitis drug (6, II, 19), although its mechanism of pharmacological action remains unclear.Recently, interferon (IFN) with or without adenine arabinoside (Ara-A) has been used to treat hepatitis B patients (4, 7). Studies show that IFN consistently decreases the level of either DNA polymerase or hepatitis B surface antigen in hepatitis patients. There are also many reports which suggest that some irnmunopotentiators induce IFN (13) and explain their antiviral activity in vivo as interferon mediated (8,16,18). Therefore, in the light of GL's clinical effect on hepatitis patients and of the fact that its structure resembles that of hydrocortisone, the possibility that GL induces IFN was proposed. In this study we investigated the ability of both GL and GA to induce IFN in mice.Six-to 8-week-old male DDI mice obtained from the Institute for Experimental Animals, Tohoku University School of Medicine, were used in this experiment. Six-week-old male C3H, ddY, CDF-l, C57BL, BALB/c, and athymic nude mice (nujnu) of BALB/c background were obtained from the Funabashi Farm Co., Ltd., and were used to study the effect of the different mouse strains on interferon induction.GL and GA were supplied by Minophagen Pharmaceutical Co. Drugs were dissolved in 0.01 M phosphate buffered saline (PBS) and adjusted to pH 7.2 with I N sodium hydroxide.Pooled sera obtained from three mice were tested for anti-viral activity, which was determined by the 50% plaque reduction method on L-929 monolayer cell cultures with vesicular stomatitis virus (VSV) and was expressed in international reference units based on NIH reference mouse IFN (Catalog No. 002-904-511) (12).

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After immunizing 8-month pregnant Holstein cows with human rotavirus, Wa strain, cow colostrum containing neutralizing antibody to human rotavirus, designated as Rota colostrum, was obtained. After randomly grouping 13 infants from a single orphanage, 6 infants received 20 ml of Rota colostrum every morning and 7 control infants received 20 ml of market milk. One month later, rotavirus associated diarrhea was observed in 6 of the 7 infants given milk and 1 out of the 6 infants given Rota colostrum. Orally administered Rota colostrum significantly protected infants from diarrhea caused by rotavirus (P less than 0.05). Two out of 5 Rota colostrum recipients who were free from diarrhea showed rises in complement fixation (CF) antibody titer after the rotavirus infection epidemic. Thus, Rota colostrum prevented the outbreak of diarrhea but did not prevent immunological responses to natural rotavirus infection. In the therapeutic trial Rota colostrum had no effect on duration of diarrhea, bowel movements or virus shedding in stool. However, there were no side-effects of Rota colostrum.

After oral administration of an organic germanium compound , Ge-132 (300 mg/kg), a significant level of interferon (IFN) activity was detected in the sera of mice at 20 hr and it reached a maximum of 320 Uiml at 24 hr. This IFN activity was lost after heat-or acid-treatment, suggesting that the induced IFN is of 7-nature . The molecular weight of this IFN was estimated to be 50,000 daltons by gel filtration . The NK activity of spleen cells was increased 24 hr after the oral administration of Ge-132, and cytotoxic macrophages were induced in the peritoneal cavity by 48 hr . In the mice receiving an intraperitoneal (ip) injection of trypan blue or carrageenan 2 days before oral administration of Ge-132, neither induction of IFN nor augmentation of NK activity occurred, and X-ray irradiation of mice also rendered the mice incapable of producing IFN, all indicating that both macrophages and lymphocytes are required for this IFN induction. Both NK and cytotoxic macrophages appeared 18 hr after ip administration of the induced IFN with a titer as low as 20 U/ml. These facts suggest that both the augmentation of NK activity and activation of macrophages in mice after oral administration of Ge-132 are mediated by the induced IFN.