Augmentation of macrophage phagocytosis by modified arabinoxylan rice bran (MGN-3/biobran)

Immune-enhancing effect of Danggwibohyeoltang, an extract from Astragali Radix and Angelicae gigantis Radix, in vitro and in vivo

Danggwibohyeoltang (DGBHT) is an oriental herbal prescription consisting of two herbs: Astragali Radix and Angelicae gigantis Radix. We examined the immune-enhancing effect of DGBHT in mice using the forced swimming test (FST) and in vitro tests in peritoneal macrophages. After daily oral administration of DGBHT, blood biochemical parameters related to fatigue were measured after the FST. The immobility time in the FST was significantly decreased in the DGBHT-treated group (200 mg/kg) on the 10th and 14th days. DGBHT (100~~200 mg/kg) treatment significantly increased glucose levels, acting as an energy source. Lactic dehydrogenase levels, which are accurate indicators of muscle damage, tended to decline after DGBHT administration (100~200 mg/kg). When DGBHT (200 mg/kg) was orally administered to mice, creatine kinase levels tended to decrease; however, this decrease was not significant. DGBHT did not have any effects on the variation of total protein and blood urea nitrogen levels. Further, we examined how DGBHT regulates cytokine production, nitric oxide (NO) production, and nuclear factor-kappa B (NF-κB) activation in mouse peritoneal macrophages. When DGBHT was used in combination with recombinant interferon-gamma (rIFN-γ), there was a noticeable cooperative induction of NO production and NF-κB activation. Moreover, rIFN-γ plus DGBHT treatment of peritoneal macrophages significantly increased the production of tumor necrosis factor-alpha (TNF-α) and interleukin-12 (IL-12). These results suggest that DGBHT improves immune function through the changes in indicators related to fatigue and the regulatory effects on immunological parameters, such as TNF-α, IL-12, NO production, and NF-κB activation.

Inhibition of degranulation and cytokine production in bone marrow-derived mast cells by hydrolyzed rice bran

OBJECTIVE

We investigated the effects of hydrolyzed rice bran (HRB), an arabinoxylan extracted from rice bran, on mast cell degranulation and cytokine production.

MATERIALS AND METHODS

HRB was obtained by treating rice bran with an extract obtained from shiitake mushrooms. Bone marrow-derived mast cells (BMMCs) were prepared by culturing bone marrow cells from BALB/c mice in the presence of interleukin-3 and stem cell factor for 4 weeks. BMMCs were pretreated with HRB (0-3 mg/ml) for 30 min and were then antigen activated.

RESULTS

Pretreatment of BMMCs with HRB significantly inhibited antigen-induced degranulation and cytokine production (tumor necrosis factor-alpha and interleukin-4) in a dose-dependent manner. HRB also diminished membrane fusion between liposomes in which soluble N-ethyl maleimide-sensitive factor attachment protein receptors were reconstituted. Phosphorylation of RelA and mitogen-activated kinases after antigen stimulation was suppressed by pretreatment of BMMCs with HRB.

CONCLUSIONS

These findings suggest that HRB may have an anti-inflammatory effect by inhibiting mast cell degranulation and cytokine production.

Saccharomyces cerevisiae, the Baker's Yeast, suppresses the growth of Ehrlich carcinoma-bearing mice

This study was undertaken to evaluate the effectiveness and mechanisms of anti-tumor activity of Baker's yeast, Saccharomyces cerevisiae, in immunocompetent mice. Swiss albino mice were inoculated intramuscularly in the right thigh with Ehrlich Ascites Carcinoma (EAC) cells. At day 8, mice bearing Solid Ehrlich Carcinoma tumor (SEC) were intratumorally (IT) injected with killed S. cerevisiae (10 x 10(6) and 20 x 10(6) cells) for 35 days. Histopathology of yeast-treated mice showed extensive tumor degeneration, apoptosis, and ischemic (coagulative) and liquefactive necrosis. These changes are associated with a tumor growth curve that demonstrates a significant antitumor response that peaked at 35 days. Yeast treatment (20 x 10(6) cells) three times a week resulted in a significant decrease in tumor volume (TV) (67.1%, P < 0.01) as compared to PBS-treated mice. The effect was determined to be dependent on dose and frequency. Yeast administered three and two times per week induced significant decrease in TV as early as 9 and 25 days post-treatment, respectively. Administration of yeast significantly enhanced the recruitment of leukocytes, including macrophages, into the tumors and triggered apoptosis in SEC cells as determined by flow cytometry (78.6%, P < 0.01) at 20 x 10(6) cells, as compared to PBS-treated mice (42.6%). In addition, yeast treatment elevated TNF-alpha and IFN-gamma plasma levels and lowered the elevated IL-10 levels. No adverse side effects from the yeast treatment were observed, including feeding/drinking cycle and life activity patterns. Indeed, yeast-treated mice showed significant final body weight gain (+21.5%, P < 0.01) at day 35. These data may have clinical implications for the treatment of solid cancer with yeast, which is known to be safe for human consumption.

Modified Arabinoxylan Rice Bran (Mgn-3/Biobran) Enhances Intracellular Killing of Microbes by Human Phagocytic Cells in Vitro

Phagocytic cells, comprised of neutrophils and moncytyes/macrophages, play a key role in the innate immune response to infection. Our earlier study demonstrated that arabinoxylan rice bran (MGN-3/Biobran) activates murine peritoneal macrophage and macrophage cell lines. In this study, we investigated whether MGN-3 can upregulate the phagocytic activity of human phagocytes in peripheral blood to phagocytize Escherichia coli (E. coli), trigger the oxidative burst and produce cytokines. Phagocytic cells were pre-labeled with dichlorofluorescin diacetate dye and were incubated with phycoerythrin-labeled E. coli in the presence or absence of MGN-3. Phagocytosis and oxidative burst were assessed by flow cytometry. Results showed that treatment with MGN-3 enhanced the phagocytosis of E. coli by neutrophils and moncytes. This was associated with an increased oxidative burst. In addition, it caused a significant induction of cytokines (TNF-α, IL-6, IL-8 and IL-10); the effect was detected at 1 μg/ml and increased in a dose-dependent manner (P≤ 0.01). Notably, MGN-3 alone had no effect on the growth of 31 strains of bacteria suggesting that MGN-3 modulates phagocytic cellular function. These findings may have applications in the treatment of infections in the elderly and in immunocompromised patients.

Rice (Oryza sativa L.) inhibits growth and induces differentiation of human leukemic U937 cells through activation of peripheral blood mononuclear cells

Rice (Oryza sativa L.) is a staple food worldwide for centuries. In this study, the growth-inhibiting and immunopotentiating effects of commonly used rice were examined. The growth of human leukemic U937 cells was significantly inhibited by the peripheral blood mononuclear cell-conditioned medium (MNC-CM) derived from water extracts of Japonica rice milled Taiwan 9 (MT9) and brown Taiwan 9 (BT9). Furthermore, these MNC-CMs induced differentiation of U937 cells into mature monocytes/macrophages expressing superoxide-producing and phagocytic activity. The amounts of tumor necrosis factor-alpha and interferon-gamma in MNC-CMs prepared with MT9 and BT9 were greater than normal MNC-CM. However, growth of U937 cells was not inhibited by normal MNC-CM or rice extracts alone. The possible active components of MT9 and BT9, other than PHA-like glycoproteins and heat-sensitive proteins and lipopolysaccharides, remain to be determined. Our results demonstrate that MT9 and BT9 can inhibit growth and induce differentiation of leukemic U937 cells through activation of human peripheral blood MNC in vitro. These two types of rice as energy-providing food could be biological response modifiers for augmenting anti-leukemia immunity.

Phagocytosis of apoptotic cells and immune regulation

The termination of the apoptotic programme occurs in most cases via recognition and clearance by phagocytes, especially the professional phagocytes, such as macrophages and immature dendritic cells. Engulfed cells do not simply disappear from the midst of living tissues. The fine-defined presentation of yielded self-antigens to T cells is a central event in the induction or the maintenance of the peripheral immune tolerance to self. Conversely, abnormality in this pathway may contribute to the pathogenesis of systemic and organ-specific autoimmune diseases. We herein reviewed the relationship between phagocytosis of apoptotic cells and immune regulation, especially the effects of engulfed apoptotic cells on immune tolerance and autoimmune diseases.

Antioxidant vitamins reduce oxidative stress and ventricular remodeling in patients with acute myocardial infarction

We analyzed soluble vascular adhesion molecules (sVCAM-1), reactive oxygen metabolites (ROMs) level, total antioxidant status (TAS) and telediastolic left ventricular volume (TLVV) in patients with myocardial infarction undergoing reperfusion therapy and treated with antioxidant vitamins (AT) or placebo (P) before and for 1 month after reperfusion. After reperfusion, sVCAM-1 serum concentration, reactive oxygen metabolites level, and TLVV were significantly higher in patients treated with placebo than in those treated with antioxidant vitamins, while TAS was significantly higher in patients treated with antioxidant supplementation. We observed that 48 hours after reperfusion sVCAM-1 (P) vs sVCAM-1 (AT) was 2.03+/-0.5 vs 1.63+/-0.7 microg/ml with p < 0.01; ROMs (P) vs ROMs (AT) were 335.60+/-35.80 vs 307.50+/-47.10 U.CARR with p < 0.05; TAS (P) vs TAS (AT) was 526.47+/-44.24 vs 737.65+/-51.15 micromol/l with p < 0.01; 1 week after reperfusion TLVV (P) vs TLVV (AT) was 125.12+/-29.80 vs 119.40+/-29.40 ml with p < 0.05; 1 month after reperfusion TLVV (P) vs TLVV (AV) was 132.00+/-33.50 vs 123.40+/-21.60 ml with p < 0.05. In the first period after infarction, vitamin treatment improves the antioxidant system and reduces oxidative stress, inflammatory process and left ventricular remodeling.