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Results for “Immune function”

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At least 1,477 records · Page 82Linked to original sources
PubMed1993

Constitutive expression of high levels of soluble mouse CD4 in transgenic mice does not interfere with their immune function.

Interactions of CD4 with the major histocompatibility complex (MHC) class II molecules are crucial during thymic development and subsequently for the function of single-positive CD4+CD8- T lymphocytes. Here, we have investigated the potential effects of soluble CD4 (sCD4) on the immune system. We generated two different transgenic mouse lines, which constitutively expressed either approximately 100 micrograms/ml of monovalent or approximately 20 micrograms/ml of decavalent mouse sCD4 molecules in their sera. Analysis of these mice revealed no differences compared to control littermates, e.g. the single-positive CD4+ cells developed normally and these cells responded to allogeneic and anti-CD3 antibody stimuli like the cells from control mice. Furthermore, the T helper cell function for antibody responses in vivo were not affected. Our data provide evidence that, in mouse, the CD4-MHC class II-interaction has very low affinity. Since sCD4 is considered to be a therapeutical agent for human immunodeficiency virus infection, these findings are not only of basic, but also of clinical interest.

Animals↗
PubMed1995

Castration alters peripheral immune function in normal male mice.

While it is generally recognized that females show enhanced cell-mediated and antibody responses to antigenic stimulation, the physiological basis for this observed sexual dimorphism of the immune response is not well understood. We report here studies on the effects of androgen deficiency on the peripheral immune system. Intact male mice were compared to animals castrated 3-4 months previously. Phenotypic characterization of thymocyte and lymphocyte subpopulations was carried out using dual-colour flow cytometry. In vitro production by spleen cells of interleukin-2 (IL-2), IL-4 and interferon-gamma (IFN-gamma), and levels of total immunoglobulin and autoreactive antibodies was measured by specific immunoassays. In addition to thymic hypertrophy, castrated animals showed significant splenic enlargement, which was largely owing to expansion of the B-cell population. The castrated spleens contained relatively fewer mature T cells than intact controls (P < or = 0.001), but culture supernatants from these spleen cells contained higher levels of IL-2 and IFN-gamma than control cultures (P < 0.04). Levels of in vitro antibody synthesis (IgM, IgG, IgA) were not higher in castrated animals compared to controls, but the castrate spleen cell cultures showed increased levels of production of two autoreactive antibodies, anti-IgG (rheumatoid factor) and anti-thyroglobulin. These data suggest that androgen deprivation results in a relative decrease in the number of mature peripheral T cells, but those which reach the spleen have functional characteristics suggestive of enhanced activation. Dysregulation in the B-cell compartment may be the result of altered effects of T-cell-mediated control.

Androgens↗
PubMed2006

A natural sweetener, Momordica grosvenori, attenuates the imbalance of cellular immune functions in alloxan-induced diabetic mice.

Momordica grosvenori (MG), a traditional medicinal herb in China used as a substitute sugar for obese and diabetic patients, exhibited an enhancement of immunity. Heme oxygenase-1 (HO-1) is among the acute phase proteins that play an important role in the inflammatory process and have antiinflammatory activities with their antioxidant properties. The hypothesis that MG could modulate an imbalance of the cellular immune system and prevent the progression of diabetes mellitus, via induction of HO-1 protein expression was investigated. Diabetes was induced in male Balb/c mice by intraperitoneal injection of alloxan (200 mg/kg). The mice were randomly assigned to non-diabetic and diabetic groups, and further subdivided according to their treatments: control (distilled water), low dose MG (150 mg/kg) and high dose MG (300 mg/kg), which were administered by gavage in 24 h cycles over a 30 day period. MG administration effectively regulated the immune imbalance in diabetic mice, principally by upregulating the CD4(+) T lymphocyte subsets, and remodeling the intracellular cytokine profiles (reducing the expression of pro-inflammatory Th1 cytokines towards a beneficial Th2 pattern), ascribed to its induction and upregulation of HO-1. In conclusion, MG exhibited antidiabetic effects and may be used as a new natural drug for the treatment of diabetes.

Alloxan↗
PubMed2003

Surgical sepsis: dysregulation of immune function and therapeutic implications.

Sepsis is defined clinically as the systemic inflammatory response of the host to the documented systemic infection. The pathophysiological disturbance involves both the innate and adaptive immune systems encompassing cellular immunity, humoral components and the complement system. Dendritic cells (antigen-presenting cells) are key cells involved in the regulation of the immune response in sepsis, in particular in activating T cells and especially inducing the production and secretion of specific cytokines. These are the main mediators in establishing prominent disturbances of inflammation in patients with sepsis. The clinical features of the sepsis syndrome may vary from minor clinical disturbances to severe multiple organ failure and death of the host. Appropriate therapeutic strategies for patients with sepsis utilise conventional therapy and new novel forms of treatment, which are showing promise for the future.

Cytokines↗
PubMed1980

Zinc and immune function in Down's syndrome.

Low levels of zinc in serum and high in blood clots were found in 12 patients with Down's syndrome (DS). They also had an immune deficiency characterized by depressed neutrophil chemotaxis, skin hypersensitivity and lymphocyte responsiveness to PHA in vitro. The patients received zinc sulphate, corresponding to 135 mg Zn++ daily. After treatment for 2 months' serum zinc levels had increased, neutrophil chemotactic responsiveness was normal in 11 of the 12 patients and there were improved lymphocyte responses to high doses of PHA in vitro. Delayed skin reactivity to DNCB was also improved in 10 of 11 patients after zinc therapy. Zinc deficiency may in part explain the increased susceptibility to infection in DS.

Adolescent↗
PubMed2006

Novel anti-cholesterol monoclonal immunoglobulin G antibodies as probes and potential modulators of membrane raft-dependent immune functions.

Natural autoantibodies against cholesterol are present in the sera of all healthy individuals; their function, production, and regulation, however, are still unclear. Here, we managed to produce two monoclonal anti-cholesterol antibodies (ACHAs) by immunizing mice with cholesterol-rich liposomes. The new ACHAs were specific to cholesterol and to some structurally closely related 3beta-hydroxyl sterols, and they reacted with human lipoproteins VLDL, LDL, and HDL. They bound, usually with low avidity, to live human or murine lymphocyte and monocyte-macrophage cell lines, which was enhanced substantially by a moderate papain digestion of the cell surface, removing some protruding extracellular protein domains. Cell-bound ACHAs strongly colocalized with markers of cholesterol-rich lipid rafts and caveolae at the cell surface and intracellularly with markers of the endoplasmic reticulum and Golgi complex. These data suggest that these IgG ACHAs may serve as probes of clustered cholesterol (e.g., different lipid rafts) in live cells and thus may also have immunomodulatory potential.

Antibodies, Monoclonal↗
PubMed1999

Dietary effect of tocopherols and tocotrienols on the immune function of spleen and mesenteric lymph node lymphocytes in Brown Norway rats.

The immunoregulatory effects of dietary alpha-tocopherol (Toc) and tocotrienols (T-3) on humoral and cell-mediated immunity and cytokine productions were examined in Brown Norway rats. We found that the IgA and IgG productivity of spleen and mesenteric lymph node (MLN) lymphocytes was significantly enhanced in the rats fed on Toc or T-3, irrespective of concanavalin A (Con A) stimulation of the lymphocytes. On the contrary, the IgE productivity of lymphocytes from the rats fed on Toc or T-3 was less without Con A stimulation, but was greater in the presence of Con A, especially in the T-3 group. Toc or T-3 feeding significantly decreased the proportion of CD4+ T cells and the ratio of CD4+/CD8+ in both spleen and MLN lymphocytes of the rats fed on Toc or T-3. The interferon-gamma productivity of MLN lymphocytes was higher in the rats fed on Toc or T-3 than in those fed on a control diet in the presence of Con A, while that of spleen lymphocytes was lower in the rats fed on Toc or T-3. In addition, T-3 feeding decreased the productivity of tumor necrosis factor-alpha of spleen lymphocytes, while it enhanced the productivity of MLN lymphocytes. These results suggest that oral administration of Toc and T-3 affects the proliferation and function of spleen and MLN lymphocytes.

Animals↗
PubMed1995

Prenatal stress alters immune function in the offspring of rats.

Pregnant rats were either exposed to restraint under bright lights for 45 min three times daily (n = 7) or were left undisturbed (n = 8) during Days 14-21 of gestation. Offspring were tested for cellular immune responses as measured by Concanavalin A-stimulated proliferation and Natural Killer (NK) cytotoxicity of splenocytes as juveniles or adults, or were tested for specific humoral immune responses to in vivo challenge with the antigen Keyhole Limpet Hemocyanin (KLH) as adults. Results indicated that: (a) Proliferation did not vary as a function of sex or prenatal treatment in either juvenile or adult offspring; (b) in juveniles NK cytotoxicity was marginally lower in males as compared to females, and was also marginally reduced by prenatal stress in males but not females, whereas in adults, NK cytotoxicity was marginally enhanced by prenatal stress in both sexes; and (c) prenatally stressed offspring of both sexes had higher levels of anti-KLH antibodies as compared to controls.

Aging↗
PubMed1996

Immune function and host defense in rodents exposed to 60-Hz magnetic fields.

This study was conducted to evaluate the influence of subchronic exposure to pure, linearly polarized 60-Hz magnetic fields (MF) on the host immune response in mice. The experimental design was as follows: three groups were exposed continuously (18.5 hr/day) to MF at field strengths of 0.02, 2, or 10 gauss (G), one group was exposed intermittently (1 hr on/1 hr off) to MF at a field strength of 10 G, and one group served as a sham control. Experimental endpoints included spleen and thymus weights and cellularity, antibody-forming cell (AFC) response, delayed-type hypersensitivity (DTH) response, splenic lymphocyte subset analysis, susceptibility to infection with Listeria monocytogenes, and natural killer (NK) cell activity. No differences in body weight, lymphoid organ weight, or lymphoid organ cellularity were observed in any MF-exposed group in comparison to sham controls. Likewise, no statistically significant differences were found in comparisons of AFC responses. Isolated statistically significant differences from control were observed in MF-exposed mice in the DTH assay, although no clear dose-related pattern of altered activity was seen. Splenic lymphocyte subset parameters examined were within normal limits in all groups, and no differences between control and MF-exposed mice were found. Host resistance to bacterial infection was not altered at any MF exposure examined in this study. Finally, although apparently dose-related, statistically significant alterations were observed in an initial study of NK cell function, repeat studies failed to demonstrate a consistent pattern of alteration.

Animals↗
PubMed1997

Attendance at religious services, interleukin-6, and other biological parameters of immune function in older adults.

OBJECTIVE: First, to examine and explain the relationship between religious service attendance and plasma Interleukin-6 (IL-6) levels, and second, to examine the relationship between religious attendance and other immune-system regulators and inflammatory substances. METHODS: During the third in-person interview (1992) of the Establishment of Populations for Epidemiologic Studies of the Elderly (EPESE) project, Duke site, 1718 subjects age sixty-five or over had blood drawn for analysis of immune regulators and inflammatory factors, including IL-6 measurements. IL-6 was examined both as a continuous variable and at a cutoff of 5 pg/ml. Information on attendance at religious services was available from the 1992 interview and two prior interviews (1986 and 1989). RESULTS: Religious attendance was inversely related to high IL-6 levels (> 5 pg/ml), but not to IL-6 measured as a continuous variable. Bivariate analyses revealed that high religious attendance in 1989 predicted a lower proportion of subjects with high IL-6 in 1992 (beta-.10, p = .01) High religious attendance in 1992 also predicted a lower proportion of subjects with high IL-6 levels in 1992 (beta-.14, p = .0005). When age, sex, race, education, chronic illnesses, and physical functioning were controlled, 1989 religious attendance weakened as a predictor of high IL-6 (beta-.07, p = .10), but 1992 religious attendance retained its effect (beta-.10, p = .02). When religious attenders were compared to non- attenders, they were only about one-half as likely to have IL-6 levels greater than 5 ng/ml (OR 0.58, 95% CI 0.40-0.84, p < .005). Religious attendance was also related to lower levels of the immune-inflammatory markers alpha-2 globulin, fibrin d-dimers, polymorphonuclear leukocytes, and lymphocytes. While controlling for covariates weakened most of these relationships, adjusting analyses for depression and negative life events had little effect. CONCLUSIONS: There is a weak relationship between religious attendance and high IL-6 levels that could not be explained by other covariates, depression, or negative life events. This finding provides some support for the hypothesis that older adults who frequently attend religious services have healthier immune systems, although mechanism of effect remains unknown.

Adaptation, Psychological↗
PubMed2002

Effect of a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin on immune function in male NC/Nga mice.

Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immunosuppression in humans and animals. However, the effect of TCDD on Th2-type immune responses such as allergic reactions has been unclear. Using NC/Nga mice that developed atopic dermatitis-like skin lesions with marked elevation in plasma of total IgE when bred under conventional conditions, we investigated the effects of a single oral dose of TCDD on immune responses. NC/Nga mice received a single oral dose (0 or 20 microg/kg body weight) of TCDD. On day 7, treatment with TCDD alone decreased the cellularity of thymus. However, treatment with TCDD modified the cellularity of spleens and mesenteric lymph nodes (MLNs) but not of the thymus on day 28. When NC/Nga mice received ip immunization with OVA and alum on the same day as the TCDD treatment (0, 5, or 20 microg/kg body weight), TCDD markedly suppressed the concentrations of Th2-type cytokines (e.g., IL-4 and IL-5) in culture supernatants of spleen cells, whereas IFN-gamma production significantly increased. TCDD exposure reduced anti-OVA and total IgE antibody titers in plasma and did not induce the development of atopic dermatitis-like lesions in the pinnae or dorsal skin of NC/Nga mice. These results suggest that in NC/Nga mice, exposure to TCDD may impair the induction of Th2-type immune responses.

Administration, Oral↗
PubMed2005

A half-marathon and a marathon run induce oxidative DNA damage, reduce antioxidant capacity to protect DNA against damage and modify immune function in hobby runners.

This study investigated whether a 21.1 km (half-marathon) or a 42.195 km (marathon) run modulates DNA damage, antioxidant capacity in lymphocytes and plasma, and the immune system in healthy hobby runners. Ten and 12 volunteers who completed the Baden-Marathon race in Karlsruhe with a running distance of 21.1 km and 41.195 km, respectively, were assessed 10 days before and immediately after the finish. There was no increase in the levels of endogenous DNA strand breaks immediately after half-marathon or marathon races. A statistically significant increase in the levels of oxidative DNA damage in lymphocytes was found using endonuclease III but not formamidopyrimidine glycolase (Fpg). The resistance of DNA to oxidative damage induced by hydrogen peroxide in isolated lymphocytes was significantly decreased after both races. The levels of plasma antioxidants such as alpha-tocopherol, beta-carotene and lycopene were close to, or higher than, those considered optimal for reducing the risk of cardiovascular diseases and there were no significant changes after the races in antioxidant capacity of LDL (lag-time test) or plasma in ORAC, TEAC or paraoxonase assays. The number and percentage of granulocytes and monocytes able to generate oxidative burst were significantly increased after both races, but the lytic activity of NK cells was significantly increased at the end of the half-marathon; no effect was observed in the marathon runners. Thus, oxidative DNA damage in lymphocytes, decreased the antioxidant capacity to protect lymphocytes against DNA strand breaks and increased the formation of reactive species by phagocytes in well-nourished hobby runners indicating moderate oxidative damage during such high-intensity exercise.

Adult↗