Prechallenge high neutralizing antibodies and long-lasting immune reactivity to gp41 correlate with protection of rhesus monkeys against productive simian immunodeficiency virus infection or disease development.

To investigate the protective efficacy of various gp130 vaccine preparations, rhesus monkeys were immunized with gp130 oligomers (O-gp130) or two different gp130-monomer preparations (M1-gp130; M2-gp130) and challenged with 50 MID50 of simian immunodeficiency virus (SIV)mac32H. Following challenge the control animals and all animals of the M1- and M2-gp130 group and 1 animal of the O-gp130 group were productively infected, whereas 3 animals of the O-gp130 group resisted the productive virus replication. The protection was correlated with high neutralizing antibodies and a long-lasting immune response to the transmembrane protein gp41. Whereas none of the O-gp130 animals had developed disease symptoms, 3 M1-gp130 animals, 1 M2-gp130 animal, and 2 control animals died as a result of AIDS within 18 months after challenge. Therefore, immunization with virion-derived gp130 oligomers of SIVmac32H can confer protection against the productive infection with SIVmac32H and suppress the development of the AIDS-like disease.

Inhibition of xanthine oxidase by pterins.

The effect of a panel of pterins on xanthine oxidase was investigated by measuring formation of urate from xanthine as well as formazan production from nitroblue tetrazolium. The pterin derivatives, depending on their chemical structure, decreased urate as well as formazan generation: 200 microM neopterin and biopterin suppressed urate formation (90% from baseline) and formazan production (80% from baseline) as well. Their reduced forms, 7,8-dihydroneopterin and 5,6,7,8-tetrahydrobiopterin, showed a lesser but still strongly diminishing influence (40% from baseline). Another oxidized pterin namely leukopterin showed only a weak inhibitory effect. Xanthopterin, a known substrate of xanthine oxidase, had a strong effect on urate formation (80% inhibition), but a lesser effect on formazan production (30% reduction). When iron-(III)-EDTA complex was added to the reaction mixture all the effects were more pronounced. Superoxide dismutase, which removes superoxide anion by dismutation into oxygen, decreased formazan production in addition to pterin derivatives and had a small but enhancing effect on urate formation. Also the reductant N-acetylcysteine had an additive effect to pterins to diminish formazan production in a dose-dependent way. The results of our study suggest that depending on their chemical structure pterins reduce superoxide anion generation by xanthine oxidase.

Determination of silicon in urine by inductive coupled plasma-optical emission spectroscopy.

We describe an inductive coupled plasma-optical emission spectroscopic method to determine silicon in spot urine specimens. A 6-fold standard addition series of the urine specimen ranging from 0 to 356 micromol/l silicon was applied, and the method meets the requirement of matrix compensation in a frequently changing environment. The inter-assay variation was +/-3.0%, intra-assay variations for three specimens were +/-1.7%, +/-1.1% and +/-0.84%. To compensate for physiological variations of urine density, the silicon concentrations in urine were related to urinary creatinine which was measured in parallel by reversed-phase HPLC. Urinary silicon concentrations were examined in 43 healthy controls from the local population. The 5th-95th percentile was 12.6-237 micromol/mmol creatinine. A follow-up of three people over a period of 14 days showed that intra-individual variations of urinary silicon concentrations were smaller than variations between individuals, especially when silicon is related to creatinine.

Neopterin as a prognostic parameter in patients with squamous-cell carcinomas of the oral cavity.

Concentrations of neopterin, which is produced by human monocytes/macrophages upon stimulation by interferon-gamma, were measured in urine specimens in 23 patients with squamous-cell carcinoma of the oral cavity at diagnosis and in 12 treated patients with the same disease when recurrence of the tumor was recognized. Tumor histology and routine laboratory parameters were concomitantly determined. Urinary neopterin values showed no statistically significant correlation with tumor differentiation, tumor size or patient age, but they were significantly higher in patients with a recurrent tumor. Patients were followed for up to 4 years, and the ability of all variables to predict fatal outcome was assessed. In univariate analysis, only neopterin (p = 0.01) and the variable recurrent vs. first-diagnosed tumor were significant predictors of survival. In multivariate analysis, a combination of neopterin (p < 0.01) and the variable recurrent vs. first-diagnosed tumor (p = 0.06) was found to jointly predict survival. Thus, urinary neopterin concentrations provide valuable prognostic information in patients with squamous-cell carcinoma of the oral cavity.

Neopterin levels and pulmonary tuberculosis in infants.

Neopterin is produced and released by human macrophages in response to stimulation with interferon-gamma and changes in neopterin concentrations indicate cellular immune activation. Pulmonary infection with Mycobacterium tuberculosis is also associated with increased neopterin levels in body fluids. We report the clinical course, the diagnostic results, and the urinary neopterin levels of seven children (ages 10 months-6(6/12) years) with pulmonary tuberculosis. Two of them had progressive primary tuberculosis, in one case caused by isoniazid resistance. Diagnostic criteria included chest radiographs, intradermal tuberculosis skin testing, and culture of aspirated secretions for tuberculosis. Neopterin levels were determined by high performance liquid chromatography. The five patients with uncomplicated primary disease and a good response to therapy with isoniazid, rifampin, and pyrazinamide showed no or slightly elevated neopterin levels (mean, 458 micromol/mol creatinine). In the two patients with progressive primary tuberculosis we documented excessively high neopterin levels (mean, 2170 micromol/mol creatinine). We conclude that neopterin may be a useful parameter for measuring the degree of disease activity and the response to therapy.

Serum HIV-1 RNA levels compared to soluble markers of immune activation to predict disease progression in HIV-1-infected individuals.

We assessed the value of HIV-1 RNA level compared to soluble immune activation markers, namely neopterin, beta2-microglobulin and soluble TNF receptor 75 (sTNFR-75), to predict the change in the number of CD4+ T cells over a 1-year period, the development of AIDS, and survival (median follow-up 54 months). The study population comprised a cohort of 47 individuals for the analysis of the change in CD4+ T cells and survival (20 died), and a subgroup of 31 individuals with a baseline CD4+ T cells above 200 x 10(6)/l for the development of AIDS (11 developed AIDS). HIV-1 RNA was measured from stored sera by quantitative PCR. The CD4+ T cell count obtained at study entry strongly correlated with baseline serum HIV-1 RNA levels (r=-0.47), and to a lesser extent with neopterin (r=-0.41) and beta2-microglobulin (r=-0.29). The percentage change in CD4+ T cells over a 1-year period correlated with HIV-1 RNA levels (r=-0.32, p=0.03), however, stronger correlations were found for neopterin, beta2-microglobulin and sTNFR-75 (r=-0.51, r=-0.41, r=-0.42; p< 0.01). No progression to AIDS or death was observed in individuals with baseline HIV-1 RNA levels below 20,000 copies/ml (10 of 31 and 15 of 47 individuals, respectively). A Cox's proportional hazard model to predict AIDS revealed that HIV-1 RNA, the change in CD4+ cells over a 1-year period and sTNFR-75 levels independently predict AIDS; the change in CD4+ cells, the absolute CD4+ T cell count and neopterin were jointly significant to predict death. All results were adjusted for nucleoside monotherapy. In conclusion, to improve the predictive power, quantitation of HIV-1 RNA as a 'natural history marker' may be supplemented by measurement of sTNFR-75 for 'early'-stage disease progression and neopterin for 'late'-stage disease progression.

Neopterin-induced tumor necrosis factor-alpha synthesis in vascular smooth muscle cells in vitro.

Synthesis and secretion of proinflammatory mediators like tumor necrosis factor-alpha and neopterin are common events in severe systemic inflammatory disorders, e.g. sepsis and septic shock. Recent data suggest that both substances show similarities with respect to their bioactivities. In the present study we investigated the potential interactions of neopterin and tumor necrosis factor-alpha on inducible nitric oxide synthase gene expression and nitric oxide generation in rat vascular smooth muscle cells. In addition, we studied the influence of neopterin on tumor necrosis factor-alpha synthesis in this cell type. Single stimulation of smooth muscle cells with either neopterin or tumor necrosis factor-alpha caused inducible nitric oxide synthase gene expression and nitric oxide production. Coincubation of cells with both compounds resulted in at least additive effects on nitric oxide synthesis. Quantification of tumor necrosis factor-alpha cDNA revealed a dose-dependent effect of neopterin on tumor necrosis factor-alpha gene expression. Similar results were obtained concerning the detection of tumor necrosis factor-alpha protein and the assessment of tumor necrosis factor-alpha bioactivity. These data suggest that neopterin and tumor necrosis factor-alpha are closely associated with regard to synthesis and effects, respectively. The interactions of both inflammatory mediators in vascular smooth muscle cells might contribute to the excessive release of nitric oxide observed during sepsis, thus triggering cellular destruction and multiple organ failure.

Serum neopterin, beta2-microglobulin, soluble interleukin-2 receptors, and immunoglobulin levels in healthy adolescents.

Serum biomarkers, such as neopterin, beta2-microglobulin (B2M), and soluble interleukin-2 receptors (sIL-2R), are elevated in viral infections, including HIV-1 infection, and in inflammatory conditions, autoimmune disease, and malignancies. For many of these conditions, serum levels correlate with disease activity. Application of these biomarkers in adolescents is limited by a lack of information on the range and determinants of variability (age, sex, race) for serum levels of these important molecules in this age group. To address this question, we analyzed serum samples from a well-characterized heterogeneous population of 111 healthy adolescents. White children had significantly higher serum levels of sIL-2R and IgM and lower levels of IgG (P

[Systemic changes of the immune system in patients with Alzheimer's dementia]. / Systemische Veränderungen des Immunsystems bei Patienten mit Alzheimer-Demenz.

OBJECTIVE: The etiology of Alzheimer's disease (AD) is still unknown. Recent investigations have shown that immune and inflammatory mechanisms could be of importance in the pathophysiology of AD. In this study 10 different immune parameters were measured to further investigate immunological changes in AD. PATIENTS AND METHODS: In 30 randomized patients with AD (20 females and ten males aged 74.5 +/- 6.5 years) as well as 13 controls aged 70.7 +/- 8.4 years, mostly relatives of the patients, all free of acute infection, serum concentrations of IgA, IgG, IgM, C3, C4, circulating immune complexes, sCD23, cardiolipin and the soluble cytokine receptors interleukin 2-receptor (sIL2-R) and tumor necrosis factor-receptor (sTNF-R) were measured. Diagnosis of AD was made according to NINCDS/ ADRDA criteria. The degree of dementia was determined by Mini-Mental-State-Examination (MMSE). RESULTS: Compared to the control group, patients with AD had significantly increased IgA (369,3 +/- 160,9 mg/dl vs 253.5 +/- 101.8 mg/dl [P = 0.02]), sCD23 [207.4 +/- 217.7 I. U./ml vs 80.6 +/- 35.5 I. U./ml [P = 0.004]), sIL2-R (829.6 +/- 742.1 I. U./ml vs 299.7 +/- 168.5 I. U./ml [P = 0.001]) and sTNF-R (4.6 +/- 2.0 I. U./ml vs 2.9 +/- 1.1 I. U./ml [P = 0.001]) levels. A negative correlation was seen between MMSE and sTNF-R (r = -0.34; P < 0.05). CONCLUSION: These findings indicate a chronic state of immune activation in AD and support the hypothesis of immune mediated mechanisms as part of the pathogenesis of AD. Prospective studies of the effect of anti-inflammatory drugs on the progression of AD will be needed.

Rat GTP cyclohydrolase I is a homodecameric protein complex containing high-affinity calcium-binding sites.

Recombinant rat liver GTP cyclohydrolase I has been prepared by heterologous gene expression in Escherichia coli and characterized by biochemical and biophysical methods. Correlation averaged electron micrograph images of preferentially oriented enzyme particles revealed a fivefold rotational symmetry of the doughnut-shaped views with an average particle diameter of 10 nm. Analytical ultracentrifugation and quantitative scanning transmission electron microscopy yielded average molecular masses of 270 kDa and 275 kDa, respectively. Like the Escherichia coli homolog, these findings suggest that the active enzyme forms a homodecameric protein complex consisting of two fivefold symmetric pentameric rings associated face-to-face. Examination of the amino acid sequence combined with calcium-binding experiments and mutational analysis revealed a high-affinity, EF-hand-like calcium-binding loop motif in eukaryotic enzyme species, which is absent in bacteria. Intrinsic fluorescence measurements yielded an approximate dissociation constant of 10 nM for calcium and no significant binding of magnesium. Interestingly, a loss of calcium-binding capacity observed for two rationally designed mutations within the presumed calcium-binding loop of the rat GTP cyclohydrolase I yielded a 45% decrease in enzyme activity. This finding suggests that failure of calcium binding may be the consequence of a mutation recently identified in the causative GTP cyclohydrolase I gene of patients suffering from dopa responsive dystonia.

Neopterin plasma concentrations predict the course of severe acute pancreatitis.

In a prospective, descriptive study in 25 patients with acute pancreatitis neopterin plasma concentrations were found to be associated with the severity of the disease, which was assessed using weights of the worst 17 physiological abnormalities of the APACHE-III score over a 24 h-period after hospital admission. Neopterin concentrations were higher in severe pancreatitis (n = 10) compared to mild disease, and there existed a positive exponential correlation between neopterin and the Acute Physiology Score (r = 0.66). Higher neopterin concentrations were associated with the development of multiple organ failure (p = 0.012) and death (p = 0.019). At a cut-off concentration of 12 nmol/l the sensitivity (80%) and specificity (100%) of neopterin for the discrimination between mild and severe clinical course of pancreatitis was more accurate than C-reactive protein at a risk threshold of 1.2 g/l (70% and 87%). Development of pancreatic necrosis was associated with higher neopterin concentrations than edematous pancreatitis (p < 0.001).

The activated immune system and the renin-angiotensin-aldosterone system in congestive heart failure.

OBJECTS: The aim of the study was to investigate a possible relationship between plasma renin activity, angiotensin II, serum levels of angiotensin-converting enzyme, aldosterone and markers of immune activation in congestive heart failure (CHF). PATIENTS AND METHODS: Fifty-three patients (50 male, three female, mean age 46 +/- 16 years) with congestive heart failure were studied. Twenty-eight patients had I or II NYHA class of CHF and 25 patients had III or IV NYHA class (NYHA class, mean +/- SD: 2.3 +/- 0.9). Serum neopterin concentration and hormones were measured by commercial radioimmunoassays. Serum soluble receptors of tumour necrosis factor and interleukin-2 were determined by ELISA. RESULTS: All analytes significantly correlated with NYHA classes (P < 0.05). There existed correlations between neopterin and angiotensin-converting enzyme or aldosterone (rs = 0.35 and rs = 0.36, P < 0.05). The soluble tumour necrosis factor receptor concentrations correlated with plasma renin activity (rs = 0.38, P < 0.05). CONCLUSION: The result of our study suggest that there exists some relationship between the renin-angiotensin-aldosterone system and immune activation in severe congestive heart failure, however, the associations found are rather weak.

Diatomaceous earth lowers blood cholesterol concentrations.

In this study a potential influence of diatomaceus earth to lower blood cholesterol was investigated. During 12 weeks we monitored serum lipid concentrations in 19 healthy individuals with a history of moderate hypercholesterinemia (9 females, 10 males, aged 35 - 67 years). Individuals administered orally 250 mg diatomaceous earth three-times daily during an 8 weeks observation period. Serum concentrations of cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglycerides levels were measured before study entry, every second week during the period of diatomaceous earth intake and 4 weeks after stop of intake. Compared to baseline (285.8 +/- 37.5 mg/dl = 7.40 +/- 0.97 mM) diatomaceous earth intake was associated with a significant reduction of serum cholesterol at any time point, reaching a minimum on week 6 (248.1 mg/dl = 6.43 mM, -13.2% from baseline; p<0.001). Also low-density lipoprotein cholesterol (week 4: p<0.05) and triglycerides levels decreased (week 2: p<0.05, week 4: p<0.01). Four weeks after intake of diatomaceous earth was stopped, serum cholesterol, low-density lipoprotein cholesterol and triglycerides still remained low and also the increase of high-density lipoprotein cholesterol became significant (p<0.05). Diatomaceous earth, a bioproduct, is capable of reducing blood cholesterol and positively influencing lipid metabolism in humans. Placebo-controlled studies will be necessary to confirm our findings.

Differential effect of dexamethasone on interleukin 1beta- and cyclic AMP-triggered expression of GTP cyclohydrolase I in rat renal mesangial cells.

1. Endogenous synthesis of tetrahydrobiopterin (BH4) is an essential requirement for cytokine-stimulated nitric oxide (NO) synthesis in rat mesangial cells. GTP cyclohydrolase I, the rate-limiting enzyme in BH4 synthesis, is expressed in renal mesangial cells in response to two principal classes of activating signals. These two groups of activators comprise inflammatory cytokines such as interleukin (IL)-1beta and agents that elevate cellular levels of cyclic AMP. 2. We examined the action of the potent anti-inflammatory drug dexamethasone on GTP cyclohydrolase I induction in response to IL-1beta and a membrane-permeable cyclic AMP analogue, N6, O-2'-dibutyryladenosine 3'-5'-phosphate (Bt2cyclic AMP). 3. Nanomolar concentrations of dexamethasone markedly attenuated IL-1beta-induced GTP cyclohydrolase I mRNA steady state level as well as IL-1beta-induced GTP cyclohydrolase I protein expression and enzyme activity. In contrast, dexamethasone did not inhibit Bt2cyclic AMP-triggered increase in GTP cyclohydrolase I mRNA level and protein expression, and low (1 nM) or high (1 and 10 microM) doses of dexamethasone consistently increased Bt2cyclic AMP-induced GTP cyclohydrolase activity. 4. In summary, these results suggest that glucocorticoids act at several levels, critically dependent on the stimulus used, to control GTP cyclohydrolase I expression.

Streptococcal erythrogenic toxins induce tryptophan degradation in human peripheral blood mononuclear cells.

BACKGROUND: In various cells including monocytes the cytokine interferon-gamma as well as lipopolysaccharide induce indoleamine 2,3-dioxygenase which degrades tryptophan to form L-kynurenine. We addressed the question of whether the exposure of human peripheral mononuclear cells to superantigens derived from streptococci is associated with tryptophan degradation in vitro. METHODS: Peripheral blood mononuclear cells were exposed to streptococcal erythrogenic toxins A and B and a streptococcal-derived mitogen named BX. In addition, the myelomonocytic cell line THP-1 was treated with these toxin preparations. RESULTS: In peripheral blood mononuclear cells all three toxins induced tryptophan degradation. In parallel, production of interferon-gamma was found, and the tryptophan degradation could be blocked by antihuman interferon-gamma antibodies. Tryptophan degradation was not induced when the human myelocytoma cell line THP-1 was stimulated with these toxins, but there was a costimulatoty effect to interferon-gamma. CONCLUSIONS: In peripheral blood mononuclear cell culture streptococcal erythrogenic toxins are able to stimulate tryptophan degradation in humans via the induction of interferon-gamma production. There seems to be no direct effect on myelomonocytic THP-1 cells. Because some of the degradation products of tryptophan, such as quinolinic acid and kynurenic acid, are toxic, superantigen-driven degradation oftryptophan may play a role for example in the development of the toxic-shock-like syndrome associated with severe group A streptococcal infections.

Increased peripheral mononuclear cells expression of adhesion molecules in alcoholic cirrhosis: its relation to immune activation.

BACKGROUND/AIMS: Cell adhesion phenomena are relevant in the immune mechanisms leading to organ damage in various diseases. Patients with alcoholic cirrhosis present with immune alterations that include findings of immunodeficiency and indications of an activated immune response. METHODS: In 37 patients with alcoholic cirrhosis we have determined the expression of surface antigens and adhesion molecules on peripheral lymphocytes and monocytes, serum levels of immunoglobulins, circulating cytokines, namely tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta, serum soluble intercellular adhesion molecule and neopterin. RESULTS: In patients, we found an increased expression of several adhesion molecules ICAM-1, LFA-3 and MAC-1 in lymphocytes, LFA-3 in monocytes and surface activation markers CD71 and DR in lymphocytes, as well as increased concentrations of the serum parameters measured: IgA, IgG, IgM, interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, soluble ICAM-1 and neopterin, in comparison with controls. CONCLUSIONS: The enhancement of the adhesion phenomena in circulating mononuclear cells of patients with cirrhosis correlates to the severity of the disease and is related to other parameters of immune activation.

Elevated serum levels of neopterin in adult patients with polymyositis/dermatomyositis.

We determined serum concentrations of neopterin, soluble tumour necrosis factor (55 kDa) receptor (sTNF-R) and soluble interleukin-2 receptor (sIL-2R) in plasma of 44 patients with polymyositis (PM)/dermatomyositis (DM), including 15 patients with primary PM, 13 patients with primary DM, and 16 patients with myositis and systemic sclerosis in overlap. Concentrations of neopterin, sTNF-R and sIL-2R were measured using commercially available immunoassays. Serum neopterin was increased in 35 of 44 PM/DM patients (80%), sTNF-R in 14 (32%) and sIL-2R in 18 (41%) patients, respectively. There were significant correlations between serum neopterin and sTNF-R, sIL-2R and erythrocyte sedimentation rate (all P < 0.001). Neopterin, as well as sTNF-R and sIL-2R, did not correlate with clinical (neuromuscular and activities of daily living scores) and laboratory (creatine kinase levels) manifestations of myositis. Increased serum levels of neopterin were associated with non-muscular manifestations of PM/DM. In conclusion, serum neopterin appears to be a useful laboratory marker for ongoing immune activation and global disease activity in PM/DM.