Eunwha Son

Methamphetamine administration produces immunomodulation in mice.

The abuse of methamphetamine (MA) is an increasingly growing problem globally and produces serious side effects. In the present study, the immunomodulating effects of MA were examined on the immune system after MA (5 mg/kg body weight) was administered daily orally for 14 d. The immune system was evaluated by the antibody response to sheep red blood cells (SRBC; plaque assay and serum immunoglobulin [Ig] G), natural killer (NK) activity, lymphocyte subpopulations in the spleen and thymus, and concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated lymphocyte proliferation using splenocytes. Body weight, spleen weight, and thymus weight generally decreased in MA-treated mice. MA treatment induced an increase in the percentage of CD4+ cells with simultaneous decrease in the percentages of CD8+ and double-positive CD4+CD8+ in thymus. MA inhibited the IgM plaque-forming cell number, and lowered the level of IgG, the proliferation of mitogen-stimulated B and T cells, and the growth of granulocyte–macrophage colony-forming units (CFU-GM). Exposure to MA also decreased interleukin-2 production by splenocytes. In contrast, splenic NK activity in exposed mice was significantly enhanced. Taken together, data indicate that the immune system was suppressed by oral MA exposure.

Novel sulfated polysaccharide derived from red-tide microalga Gyrodinium impudicum strain KG03 with immunostimulating activity in vivo

The high-sulfate-containing exopolysaccharide p-KG03 is produced by the red-tide microalga Gyrodiniumimpudicum strain KG03. The immunostimulatory effects of this sulfated exopolysaccharide were investigated by isolating peritoneal macrophages from mice 10 or 20 days after they had received a single dose of p-KG03 (100 or 200 mg/kg body weight). The cytotoxicity of the isolated macrophages for B16 tumor cells was tested, as B16 tumor cells are sensitive to tumor necrosis factor α (TNF-α) and nitric oxide. The activities of natural killer cells from the p-KG03-treated mice against YAC-1 mouse lymphoma cells were also tested. The nonspecific immune functions mediated by natural killer cells and macrophages were increased by treatment with p-KG03 in vivo. These results suggest that p-KG03 has immunostimulatory effects and enhances the tumoricidal activities of macrophages and NK cells in vivo. In addition, p-KG03 treatment increased the plaque-forming cell response to sheep red blood cells, as well as the levels of IgM and IgG Exposure to p-KG03 also increased the production by macrophages of cytokines, such as interleukins -1β and -6, and TNF-α. This is the first report of a marine microalgal sulfated polysaccharide having immunostimulatory activities. The p-KG03 polysaccharide may be useful for the development of biotechnological and pharmaceutical products that incorporate bioactive marine exopolysaccharides.

Stimulation of various functions in murine peritoneal macrophages by high mannuronic acid-containing alginate (HMA) exposure in vivo.

High mannuronic acid-containing alginate (HMA) was tested to affect murine peritoneal macrophages. In the present study, we measured various functions of murine peritoneal macrophages that were isolated 20 h after intraperitoneal injection with HMA (25 and 100 mg/kg). HMA increased the number of peritoneal macrophages and phagocytosis. Macrophages from HMA-treated mice significantly inhibited growth of tumor cells compared to macrophages from control mice. In addition, supernatants from macrophages of HMA-treated mice contained nitric oxide (NO), hydrogen peroxide (H2O2) and TNF-alpha. The increased production of these cytotoxic molecules induced by HMA is consistent with tumoricidal activity of activated macrophages. Furthermore, HMA-induced tumoricidal activity was partially abrogated by anti-TNF-alpha, inhibitors of NO and the scavenger of reactive oxygen. Thus, the tumoricidal activity induced by HMA appeared to be mediated by the production of TNF-alpha, NO and H2O2. Taken together, these results suggest that HMA has the immunostimulating effect on macrophages after in vivo exposure of it.

The immunomodulatory effects of the herbicide simazine on murine macrophage functions in vitro

We examined the immunomodulating effects of simazine, a triazine herbicide, on murine peritoneal macrophages after in vitro pre-exposure. When thioglycollate-elicited macrophages pre-exposed to simazine were stimulated with lipopolysaccharide (LPS), the antitumor activity induced by LPS was suppressed by simazine. Simazine also inhibited poly I:C-induced antiviral activity and interferon (IFN) production in macrophages. In addition, the production of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) which have been known to be major effector molecules in macrophage-mediated cytotoxicity was decreased by simazine pretreatment in a dose-dependent manner. However, simazine had little effect on phagocytosis and the level of hydrogen peroxide (H(2)O(2)), interleukin-1 (IL-1) and IL-6 by LPS-stimulated macrophages. Taken together, these data indicate that simazine has a differential immunomodulating effect on macrophage secretory and cellular activities.

MODULATION OF MURINE MACROPHAGE FUNCTION BY METHAMPHETAMINE

The abuse of methamphetamine (MA) is an increasingly growing problem globally and produces serious side effects. In the present study, the immunomodulating effects of MA were examined on murine peritoneal macrophages after MA (5 mg/kg body weight) was administered daily orally for 2 wk. When purified macrophages were stimulated with lipopolysaccharide (LPS), the tumoricidal activity induced by LPS was significantly suppressed by MA. MA also inhibited poly I:C-induced antiviral activity in macrophages and decreased the number of peritoneal macrophages. FACS analysis showed that the expression of CD14 was markedly decreased by MA in LPS-stimulated macrophages. The production of nitric oxide (NO) and tumor necrosis factor (TNF)- α, which are known to be major effector molecules in macrophage-mediated cytotoxicity, was decreased by MA. MA produced a significant effect on phagocytosis and interleukin-1 (IL-1) and IL-6 at 14 d. In addition, the level of hydrogen peroxide (H2O2) was not altered by MA. Taken together, these data indicate that MA has a differential immunomodulating effect on macrophage secretory and cellular activities.

Immune alterations in mice exposed to the herbicide simazine

Simazine, a triazine herbicide, was investigated for its in vivo immunomodulatory properties. Male C57Bl/6 mice were treated with vehicle or 300 or 600 mg/kg body weight (bw) simazine daily orally for 4 wk. The immune system was evaluated by the antibody response to sheep red blood cells (SRBC; plaque assay and serum immunoglobulin G), natural killer (NK) and macro-phage activities, lymphocyte subpopulations in the spleen and thymus, and concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated lymphocyte proliferation using splenocytes. Body weight and spleen and thymus weight decreased generally in simazine-treated mice, while the weight of adrenal glands was higher than in the control. Simazine treatment (600 mg/kg) induced an increase in the percentage of CD4 + cells in spleen and CD8 + in thymus. Simazine inhibited the IgM plaque-forming cell numbers and lowered the level of IgG and the proliferation of mitogen-stimulated B cells and T cells. In addition, splenic NK and peritoneal macrophage activities in exposed mice were significantly decreased. Exposure to simazine also decreased cytokine production by macrophages, such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor- f (TNF- f ). Taken together, data indicate that the immune system was suppressed by oral simazine exposure.

Inhibition of γ-irradiation induced adhesion molecules and NO production by alginate in human endothelial cells

Inflammation is a frequent radiation-induced reaction following therapeutic irradiation. Treatment of human umbilical endothelial cells (HUVEC) with γ-irradiation (γlR) induces the expression of adhesion proteins such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. Since the upregulation of these proteins on endothelial cell surface has been known to be associated with inflammation, interfering with the expression of adhesion molecules is an important therapeutic target. In the present study, we demonstrate that high mannuronic acid-containing alginate (HMA) inhibits γlR induced expression of ICAM-1, VCAM-1, and E-selectin on HUVEC in a dose dependent manner. HMA also inhibited γIR induced production of Nitric oxide (NO). These data suggest that HMA has therapeutic potential for the treatment of various inflammatory disorder associated with an increase of endothelial leukocyte adhesion molecules.

Effects of supplementation with higher levels of manganese and magnesium on immune function

The magnesium (Mg) and manganese (Mn) were evaluated for its effectiveness as an immunomodulator in rats. The treatments were as follows: Group 1, AIN-93M diet (0.05% Mg, 0.001% Mn); Group 2, high-dose Mg (0.1% Mg, 0.001% Mn); and Group 3, high dose Mn (0.05% Mg, 0.01% Mn) (n-12/group). After 12 weeks of supplementation, rats were sacrificed to assess the effect on a range of innate responses (tumoricidal activity, oxidative burst and nitric oxide) and the mitogen-stimulated lymphoproliferative response. Immune function was significantly affected in both the high dose Mg and the Mn group. Lymphocyte proliferative responses and NK cell activity were measured in pooled spleen from each group. The mitogen response of lymphocytes to LPS in the spleen was significantly reduced in high dose Mg-treated groups, whereas the response to ConA was not affected in both high dose minerals-treated groups. The reactive oxygen species level of macrophages was decreased in both groups. These effects were more pronounced in high dose Mg-treated group. Nitric oxide production was also decreased in high dose minerals-treated group. In addition, tumoricidal activities of splenic NK cell and peritoneal macrophage in mineral exposed rats were significantly increased. Moreover, percent death of macrophage was reduced in two groups receiving high dose mineral supplements. Taken together, the present data suggest that high dose trace min-erals exert a differential effect on the function of immune cells.

Gamma-irradiation-induced intercellular adhesion molecule-1 (ICAM-1) expression is associated with catalase: activation of Ap-1 and JNK.

The ionizing radiation used in cancer therapy frequently produces damage to normal tissues and induces complex responses, including inflammation. The upregulation of the intercellular adhesion molecule-1 (ICAM-1) in response to numerous inducing factors is associated with inflammation. Therefore, this study examined the molecular mechanisms responsible for ICAM-1 expression induced by γ-irradiation (γIR). ICAM-1 mRNA and cell surface expression were induced in A549 human lung epithelial cells after exposing them to γIR. Catalase expression and activity were also increased in γIR-treated cells. Treatment of the γIR-treated cells with catalase resulted in a significant increase in the ICAM-1 cell surface expression level. The catalase inhibitor 3-amino-1,2,4-triazole (AT) reduced the level of ICAM-1. Electrophoretic mobility shift assay (EMSA) analysis showed that activating protein 1 (AP-1) was activated by γIR, whereas NF-κB was not. Specific Jun N-terminal kinase (JNK) inhibition attenuated the upregulation of γIR stimulated ICAM-1. Western blot analysis revealed a marked elevation in activation of JNK. In addition, pretreatment with AT resulted in a decrease in the level of JNK phosphorylation and AP-1 activation. Overall, data suggest that induction of ICAM-1 expression by γIR is associated with catalase. Furthermore, catalase, JNKs, and AP-1 activation induce ICAM-1 upregulation through a sequential process.

Antiviral and tumoricidal activities of alginate-stimulated macrophages are mediated by different mechanisms.

Macrophages play an important role in host defenses by killing tumors and virus infections and producing secretory products. High mannuronic acid (HMA) containing alginate was examined to determine the mechanisms by which HMA-activated macrophages resist infection with HSV-1 and inhibit the growth of tumor cells. The ability of macrophages to resist infection with HSV-1 or to inhibit the growth of tumor cells was assessed following treatment with HMA alginate in the presence of either antibodies to various cytokines or inhibitors/scavengers of toxic macrophage products. Only antibodies to IFN-α/β were able to abrogate the protective effects of HMA alginate in macrophages infected with HSV-1, suggesting that the antiviral activity induced by this immunomodulator was mediated by the production of IFN-β. In contrast, anti-TNF-α, anti-IFN and inhibitors of nitric oxide and reactive oxygen species were all able to partially abrogate HMA-induced cytostatic activity, suggesting that multiple mechanisms are involved in macrophage cytostasis. These results indicate that the HMA-induced intrinsic anti-viral and extrinsic cytotoxic activites are mediated by different mechanisms.