Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Preincubation of peripheral blood lymphocytes (PBL) from drug-free, healthy volunteers with either the protein tyrosine kinase inhibitor genistein (GNT, n = 10, final concentration 200 microM) or the protein kinase A activator dybutiryl-cyclic-AMP (cAMP, n = 11, final concentration 10 microM), resulted in a significant inhibition of natural killer cell activity (NKCA, expressed as percentage of specific chromium release). With the exception of 4 out of the 11 cAMP-treated samples, individual values for NKCA in the drug preincubated specimens were at least 20% below the same subject baseline activity; furthermore, NKC lytic function was non-detectable in 4 out of the 10 and in 1 out of the 11 samples pretreated with either GNT or cAMP, respectively. PBL preincubation with glutaraldehyde-fixed Gram-negative bacteria (GNB, n = 13, final GNB-to-effector cell ratio of 50 : 1) resulted in a statistically significant increase in NKCA (baseline (x +/- SD) of 21.6 +/- 16.4 and bacteria treated samples of 41.5 +/- 24.6, respectively, Student's paired t-test p < 0.05). At least a 20% increase in NKC lytic function over its own baseline value was recorded for 11 out of the 13 samples tested (Table 1). Preincubation with GNB and GNT (5 samples) not only blocked the immunostimulant effects of GNB (Student's paired t-test p < 0.05), but in most cases individual values for NKCA were similar to those recorded for GNT-only treated samples. Use of cAMP instead of GNT also blocked, but to a smaller extent, the GNB-produced increases in NKC lytic function (paired Student's t-test < 0.05). PBL preincubation with lipopolysaccharide (LPS, n = 11, final concentration 50 micrograms/ml) resulted in a statistically significant increase in NKCA (baseline (x +/- SD) of 20.7 +/- 14.1 and LPS treated samples of 39.2 +/- 18.5, respectively, Student's paired t-test < 0.05). At least a 20% increase in NKCA over its own baseline value was observed for each and everyone of the 11 samples studied (Table 2). Addition of LPS and GNT to the incubation mixture resulted not only in inhibition of the NKCA upmodulating LPS effects (Student's paired t-test p < 0.05), but each and everyone of the individual samples' NKCA were, in fact, significantly lower than their corresponding control baseline values and similar to those recorded for GNT-only treated samples. However, the use of LPS and cAMP (Table 2) produced less dramatic results, significant inhibition of LPS effect were recorded in only 2 samples (Nos 8 and 10), and individual NKCA in the remaining 3 specimens was significantly higher than the corresponding baseline value. Whereas experimental results obtained with GNT support the involvement of PTK-dependent pathways in the stimulation of human NKCA produced by GNB and LPS, cAMP experiments suggest modulation of PKA-dependent pathways as responsible for the decrease in NK lytic function produced by a number of chemicals involved in the pathophysiology associated with certain forms of stress, including septic shock. Further research in this area could help in the rational design of pharmacological approaches for the treatment of these conditions.
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PMID:Activation of protein tyrosine kinase: a possible requirement for fixed-bacteria and lipopolysaccharide-induced increase in human natural killer cell activity. 873 58

Microphthalmic (mi/mi) mice are unpigmented, osteopetrotic, mast cell deficient, and exhibit diminished gastric acid secretion and natural killer cell activity. In order to assess the effect of this mutation on macrophage function, we studied superoxide (O2-) and nitric oxide (NO) production, superoxide dismutase (SOD) activity, phagocytic capacity, and tumor cell killing by peritoneal macrophages from mi/mi mice and normal (+/+) litter mates. Macrophages from mi/mi mice, upon activation with phorbol myristate acetate (PMA), generated significantly higher amounts of O2- than did macrophages from their +/+ litter mates. The phagocyte respiratory burst as assessed by nitroblue tetrazolium (NBT) reduction assay also displayed a 2-fold enhancement in mi/mi macrophages. The assay of SOD activity revealed significantly lower levels in mi/mi macrophages than in the wild type. Furthermore, in comparison with controls, macrophages from mi/mi mice demonstrated significantly higher levels of NO production and increased capacity to lyse tumor cells upon activation with lipopolysaccharide (LPS) or gamma-interferon (IFN-gamma). The mi mutation, therefore, is associated with reduced macrophage SOD activity, increased O2- and NO production, and enhanced capacity for tumor cell killing. The molecular mechanisms for these changes have not been identified.
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PMID:Macrophage function in mice with a mutation at the microphthalmia (mi) locus. 920 63

CD69, a member of the natural killer cell gene complex family of signal transducing receptors, represents one of the earliest activation antigens in human and murine lymphocytes. In contrast, human monocytes may express CD69 in a constitutive fashion. We have evaluated the expression and function of CD69 in murine bone marrow-derived macrophages. CD69 expression as determined by flow cytometry was not constitutive but was induced by stimulation with interferon-gamma (IFN-gamma) plus bacterial lipopolysaccharide (LPS) or tumor necrosis factor a (TNF-alpha). Stimulation with LPS alone was equally effective. Infection with the protozoan parasite Leishmania did not induce CD69 expression nor influence CD69 up-regulation by IFN-gamma plus LPS. Induction of CD69 expression was significantly inhibited in the presence of prostaglandin E2 or dibutyryl-cAMP. Stimulation of macrophages with anti-CD69 monoclonal antibody in the presence of IFN-gamma induced both nitric oxide production and TNF-alpha release. Moreover, anti-CD69 stimulation of Leishmania-infected macrophages resulted in elimination of the intracellular parasite. These results suggest that CD69 is an activation antigen for murine macrophages and may serve as a signaling receptor for an as yet uncharacterized ligand.
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PMID:Expression and function of the early activation antigen CD69 in murine macrophages. 930 73

We investigated the effects of (+)-4-[(alpha R)-alpha-((2S, 5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N, N-diethylbenzamide (SNC 80), a nonpeptidic delta-opioid receptor-selective agonist, on rat leukocyte functions. Intracerebroventricular injection of SNC 80 (20 nmol) in Fischer 344N male rats did not affect splenic natural killer cell activity compared with intracerebroventricular saline-injected controls. SNC 80 also had no effect on concanavalin A-, anti-T cell receptor-, interleukin-2- and anti-T cell receptor + interleukin-2-induced splenic and thymic lymphocyte proliferation in most experiments. In some experiments, however, SNC 80 significantly (P < .01) caused a 41 to 93% increase of concanavalin A-, anti-T cell receptor-, interleukin-2- and anti-T cell receptor + interleukin-2-induced splenic lymphocyte proliferation compared to controls. Additionally, SNC 80 did not significantly affect splenic T cell or natural killer cell populations as measured by the expression of T cell receptoralphabeta, and T helper (CD4), T suppressor/cytotoxic (CD8) and natural killer cell surface markers. Finally, SNC 80 did not affect interferon-gamma- or lipopolysaccharide (LPS)-induced splenic nitric oxide, and LPS-induced tumor necrosis factor-alpha production by splenic macrophages. These results suggest that SNC 80 could be useful in the treatment of pain without suppressing immune function. However, the potential immunoenhancing properties of SNC 80 may be also valuable in immunocompromised individuals.
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PMID:Rat natural killer cell, T cell and macrophage functions after intracerebroventricular injection of SNC 80. 969 52

We recently reported a positive correlation of the pool size of lipopolysaccharide receptor (CD14)dim and Fc gamma receptor IIIa (CD16a)+ monocytes in peripheral blood to the apolipoprotein E4 (apoE4) phenotype and a negative correlation to high density lipoprotein (HDL) cholesterol levels (Arterioscler Thromb Vasc Biol. 1996;16:1437-1447). In this study, the in vitro differentiation of mononuclear phagocytes derived from healthy blood donors homozygous for the E3/3 or the E4/4 phenotype was analyzed during 7 days of culture in serum-free medium supplemented with macrophage colony-stimulating factor (M-CSF). The CD16a expression, which indicates Fc receptor-dependent phagocytic activity, increased to a significantly higher level in apoE4/4 monocytes than in apoE3/3 cells. The costimulatory molecule CD40, which indicates antigen-presenting capacity, was upregulated more strongly in apoE3/3 monocytes compared with E4/4 cells, but the difference did not reach a significant level. The expression of differentiation-associated surface proteins (CD14, CD33, CD45) and adhesion molecules (CD11a, CD11b, CD11c, CD49d) was not significantly different between apoE3/3 and apoE4/4 monocytes. However, a significantly decreased intracellular apoE concentration and a reduced amount of secreted apoE were found in apoE4/4 monocytes during in vitro differentiation. No differences were found in the surface expression of the low density lipoprotein receptor-related protein (CD91) and the uptake of fluorescence labeled low density lipoprotein between apoE3/3 and apoE4/4 monocytes. These data indicate that the apoE4/4 phenotype significantly influences the M-CSF-dependent differentiation of monocytes toward a more CD16a-positive phagocytic phenotype.
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PMID:Enhanced upregulation of the Fc gamma receptor IIIa (CD16a) during in vitro differentiation of ApoE4/4 monocytes. 974 31

Aging is associated with a decline in the immune response in mammals. Conjugated linoleic acid (CLA) has been suggested to have immunoenhancing properties. We examined the influence of dietary CLA on the immune response of young and old mice. Forty young (4 mo) and 40 old (22 mo) mice consumed ad libitum diets containing 0 or 1 g CLA /100 g for 8 wk. Splenocytes from half of the mice were isolated to evaluate proliferation to concanavalin A (Con A) (0.5, 1.5, 5.0 mg/L) and phytohemagglutinin A (PHA) (5, 20, 40 mg/L) and lipopolysaccharide (LPS) (5, 15, 30 mg/L), natural killer cell (NK) activity and prostaglandin (PG)E2 and interleukin (IL)-2 production. The remaining mice were used to evaluate in vivo delayed-type hypersensitivity (DTH) skin response. There was a significant decline due to age in response to all three mitogens tested (P < 0. 05). CLA supplementation significantly increased all CLA isomers measured in hepatic neutral lipids and phospholipids (P < 0.05). Young mice fed 1% CLA had greater splenocyte proliferation in response to Con A (0.5 and 5.0 mg/L) and PHA (40 mg/L) (P < 0.05) than young mice fed control diet. Old mice fed 1 g CLA/100 g had significantly higher proliferative response to optimal concentrations of Con A (1.5 mg/L) (P < 0.001) than the mice fed the control diet. Old mice fed the control diet had significantly lower splenocyte IL-2 production than the young mice (P < 0.005). CLA-supplemented young mice had significantly higher splenocyte IL-2 production than those fed the control diet (P < 0.05). CLA had no effect on NK cell activity, PGE2 production or DTH in young or old mice. Further studies are needed to determine the mechanism of CLA-induced enhancement of IL-2 production and T cell proliferation.
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PMID:Dietary conjugated linoleic acid influences the immune response of young and old C57BL/6NCrlBR mice. 991 72

During the course of human pregnancy, glucocorticoid (GC) treatment is given when preterm delivery is expected. This treatment is successful in stimulating the development of the fetal lung. However, in animal studies, a number of side effects of perinatal GC treatment have been described. The aim of the present study was to evaluate in humans the effects of antenatal GC treatment on development of the immune system. In addition, we examined the development of immune reactivity in infants born preterm and at term who did not receive GC treatment antenatally. We tested mitogen-induced T cell proliferation, natural killer cell activity, and lipopolysaccharide-induced IL-6 production in cord blood samples. We found that there is a significant effect of gestational age on the capacity of T cells to proliferate and of natural killer cells to kill K562 tumor cells. The capacity to produce IL-6 does not change between gestational age 26 and 41 wk. Moreover, our results show that antenatal treatment with GC does have immunomodulatory effects: T cell proliferation is decreased in infants born very preterm (gestational age 26-31 wk) as well as in infants born between 32 and 36 wk of gestation. In contrast, the activity of natural killer cells is only increased in GC-treated infants born between 26 and 31 wk. We did not observe a significant effect of antenatal GC treatment on the capacity to produce IL-6.
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PMID:Altered immune function in human newborns after prenatal administration of betamethasone: enhanced natural killer cell activity and decreased T cell proliferation in cord blood. 1008 46

The influence of exercise mode and 6% carbohydrate (C) versus placebo (P) beverage ingestion on lymphocyte proliferation, natural killer cell cytotoxicity (NKCA), Interleukin (IL)-1beta production, and hormonal responses to 2.5 hr of intense running and cycling (approximately 75% VO2max) was measured in 10 triathletes serving as their own controls. The C versus P condition (but not exercise mode) resulted in higher plasma glucose concentrations, lower plasma cortisol concentrations, reduced postexercise lymphocytosis and NKCA, and a lessened T-cell reduction during recovery, No condition or mode effects were observed for concanavalin A and phytohemagglutinin-induced lymphocyte proliferation. Significant mode (but not condition) effects were observed for lipopolysaccharide-induced IL-1beta production over time. However, when expressed per monocyte, the mode effect was abolished and a sustained suppression in IL-1beta/monocyte was observed in all sessions throughout recovery. These data indicate that carbohydrate ingestion significantly affects plasma glucose and cortisol concentrations, blood lymphocyte counts, and NKCA, whereas exercise mode has no effect on these parameters.
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PMID:Influence of exercise mode and carbohydrate on the immune response to prolonged exercise. 1042 73

Fluticasone propionate is a very effective topical treatment for asthma. Interleukin-12, which is produced by monocyte-macrophage and B lymphocytic cell lines, plays an important role in the induction of Th1 cells; whereas interferon-gamma (IFN-gamma), mainly produced by Th1 cells, exhibits a crucial effect on macrophage and natural killer cell activation. Since previous studies have demonstrated a reduced production of IL-12 and IFN-gamma in patients with allergic asthma, we examined whether fluticasone propionate therapy could influence the release of these cytokines in asthma. We selected two groups of subjects (15 per group): nonatopic healthy donors (group A) and asthmatic patients (group B). Cytokine release was assessed in sera as well as in supernatants of whole blood cultures after IFN-gamma priming and lipopolysaccharide stimulation. Venous blood and spirometric tests from patients in group B were obtained before and after treatment. Fluticasone propionate therapy significantly increased interleukin-12 levels in both supernatants of blood cultures (1,152.12 +/- 225.57 vs. 540.87 +/- 130.07 pg/ml; p < 0.05) or in sera (72.24 +/- 15.76 vs. 10.83 +/- 2.70 pg/ml; p < 0.05). Patients treated with fluticasone propionate also displayed increased levels of IFN-gamma in either blood culture supernatants (59.12 +/- 16.88 vs. 18.87 +/- 7.53 IU/ml; p < 0.05) or in sera (5.60 +/- 2.87 vs. < 1 IU/ml; p < 0.05). In addition, we observed a significant increase in FEV1 values in asthmatic patients after fluticasone propionate therapy (51.86 +/- 5.31 vs. 71.46 +/- 10.37% predicted). We propose that fluticasone propionate may exert at least in part of its antiinflammatory activity through the modulation of the cytokine output.
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PMID:Effect of fluticasone propionate on interleukin-12 and interferon-gamma production in patients affected by allergic bronchial asthma. 1051 54

Local immunosuppression may explain the failure of an effective immune response against solid tumors. Although it is well known that the interstitial pH is significantly lower in solid tumors than in normal tissue, only a few studies in the mouse system have investigated the influence of this acidic milieu on the anti-tumoral cytotoxic response. Here the authors report the suppression of human non-major histocompatibility complex (MHC)-restricted cytotoxicity against tumor cells by an acidic extracellular pH (pHe). Unstimulated peripheral blood mononuclear cells, lymphokine-activated killer (LAK) cells, and natural killer cell clones were used as effector cells. According to pH measurements in solid tumors, representative pH values of 7.2 to 5.3 were chosen during the cytotoxic assays. Target cell lysis was measured using two nonradioactive fluorometric methods, namely two-color flow cytometry and a modified calcein-release assay, which allowed cell-mediated cytotoxicity to be measured and compared with that in adherent targets. Using K562, Daudi, or Raji as suspended target cell lines, the cytotoxic activity of unstimulated peripheral blood mononuclear cells and of LAK cells was markedly reduced by a decreasing pHe. An extracellular pH of 5.8 to 5.3 resulted in a nearly complete loss of the cytotoxic response. This pHe-dependent impairment of the killing activity could also be shown for killer cells stimulated with interleukins-7 and -12, phytohemagglutinin, or lipopolysaccharide. The lytic potential of homogeneous natural killer cell clones as effectors was also strictly influenced by the surrounding pH. The pHe dependence of the non-MHC-restricted killer cell functions against tumor cells seems to be a general phenomenon, because the cytolytic activity of LAK cells against six human adherent tumor cell lines (HeLa, HepG2, LS174T, LS174Te, MCF-7, and RT112) was also clearly reduced under acidic conditions. To initiate the killing process, adhesion molecules play an important role in recognition and binding of the target cell. However, flow cytometric analysis revealed that the expression pattern of relevant adhesion molecules was unaffected by acidic pHe. In conclusion, these data clearly indicate an inhibition of non-MHC-restricted cytotoxicity against tumor cells by an acidic pHe, which may contribute to the failure of immunosurveillance against solid tumors. Consequently, efforts to enhance the anti-tumoral cytotoxicity by immunotherapies may have limited success.
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PMID:An acidic microenvironment inhibits antitumoral non-major histocompatibility complex-restricted cytotoxicity: implications for cancer immunotherapy. 1074 46


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