Toward synthetic combinatorial peptide libraries in positional scanning format (PS-SCL)-based identification of CD8+ Tumor-reactive T-Cell Ligands: a comparative analysis of PS-SCL recognition by a single tumor-reactive CD8+ cytolytic T-lymphocyte clone.

The use of synthetic combinatorial peptide libraries in positional scanning format (PS-SCL) has emerged recently as an alternative approach for the identification of peptides recognized by T lymphocytes. The choice of both the PS-SCL used for screening experiments and the method used for data analysis are crucial for implementing this approach. With this aim, we tested the recognition of different PS-SCL by a tyrosinase 368-376-specific CTL clone and analyzed the data obtained with a recently developed biometric data analysis based on a model of independent and additive contribution of individual amino acids to peptide antigen recognition. Mixtures defined with amino acids present at the corresponding positions in the native sequence were among the most active for all of the libraries. Somewhat surprisingly, a higher number of native amino acids were identifiable by using amidated COOH-terminal rather than free COOH-terminal PS-SCL. Also, our data clearly indicate that when using PS-SCL longer than optimal, frame shifts occur frequently and should be taken into account. Biometric analysis of the data obtained with the amidated COOH-terminal nonapeptide library allowed the identification of the native ligand as the sequence with the highest score in a public human protein database. However, the adequacy of the PS-SCL data for the identification for the peptide ligand varied depending on the PS-SCL used. Altogether these results provide insight into the potential of PS-SCL for the identification of CTL-defined tumor-derived antigenic sequences and may significantly implement our ability to interpret the results of these analyses.

Procalcitonin and C-reactive protein in pericardial fluid for postmortem diagnosis of sepsis.

The aim of this study was to investigate the presence and concentrations of procalcitonin and C-reactive protein in pericardial fluid and compare these levels to those found in the postmortem serum obtained from the femoral blood. Two groups were formed, a sepsis-related fatalities group and a control group. Postmortem native CT scans, autopsies, histology, neuropathology and toxicology as well as other postmortem biochemistry investigations were performed in all cases. Pericardial fluid procalcitonin levels were significantly different between the cases of sepsis-related fatalities and those of the control group. Postmortem serum procalcitonin levels below the detection limit were also reflected in undetectable pericardial fluid levels. Similarly, a large increase in postmortem serum procalcitonin levels was reflected in a large increase of procalcitonin pericardial fluid levels. Based on these findings, pericardial fluid could be an alternative to postmortem serum for the determination of procalcitonin levels in cases where postmortem serum is not available and measurements of procalcitonin are required to circumstantiate the pathogenesis of death.

Reactive electrophile species activate defense gene expression in Arabidopsis.

Compounds containing alpha,beta-unsaturated carbonyl groups are increasingly implicated as potent regulators of gene expression; some are powerful cytotoxins known to accumulate at the site of lesion formation in host-pathogen interactions. We used a robust measurement of photosynthetic efficiency to quantify the toxicity of a variety of lipid derivatives in Arabidopsis leaves. Small alpha,beta-unsaturated carbonyl compounds (e.g. acrolein and methyl vinyl ketone) were highly active and proved to be potent stimulators of expression of the pathogenesis-related gene HEL (PR4). These small volatile electrophiles were far more active than larger alkenal homologs like 2(E)-hexenal, and activated HEL expression in a manner independent of salicylate, ethylene, and jasmonate production/perception. Electrophile treatment massively increased the levels of unesterified cyclopentenone jasmonates, which themselves are electrophiles. Patterns of gene expression in response to electrophile treatment and in response to avirulent bacteria were compared, which revealed strikingly similar transcript profiles. The results broaden the range of known biologic effects of reactive electrophile species to include the activation of a pathogenesis-related gene (HEL) and genes involved in metabolism. Electrophiles can act as mediators of both genetic and biochemical effects on core defense signal transduction.

Comparative localization of glioma-reactive monoclonal antibodies in vivo in an athymic mouse human glioma xenograft model.

Radioiodinated murine monoclonal antibodies (Mabs) 81C6, Me 1-14, C12, D12, and E9, made against or reactive with human gliomas but not normal brain, and Mab UJ13A, a pan-neuroectodermal Mab reactive with normal human glial and neural cells, were evaluated in paired label studies in the D-54 MG subcutaneous human glioma xenograft model system in nude mice. Following intravenous injection in the tail vein of mice bearing 200-400 mm3 tumors, specific localization of Mabs to tumor over time (6 h-9 days) was evaluated by tissue counting; each Mab demonstrated a unique localization profile. The comparison of localization indices (LI), determined as a ratio of tissue level of Mab to control immunoglobulin with simultaneous correction for blood levels of each, showed Mabs 81C6 and Me 1-14 to steadily accumulate in glioma xenografts, maintaining LI from 5-20 at 7-9 days after Mab injection. Mab UJ13A peaked at day 1, maintaining this level through day 2, and declining thereafter. Mabs D12 and C12 peaked at days 3 and 4, respectively, and E9 maintained an LI of greater than 3 from days 3-9. Percent injected dose localized/g of tumor varied from a peak high of 16% (81C6) to a low of 5% (Me 1-14 and UJ13A). Immunoperoxidase histochemistry, performed with each Mab on a battery of primary human brain neoplasms, revealed that Mabs 81C6 and E9, which demonstrated the highest levels of percent injected dose localized/g of tumor over time, reacted with antigens expressed in the extracellular matrix. This finding suggests that extracellular matrix localization of antigen represents a biologically significant factor affecting localization and/or binding in the xenograft model used. The demonstration of significant localization, varied kinetics and patterns of localization of this localizing Mab panel warrants their continued investigation as potential imaging and therapeutic agents for human trials.

Melt variability in percolated peridotite: an experimental study applied to reactive migration of tholeiitic basalt in the upper mantle

Melt-rock reaction in the upper mantle is recorded in a variety of ultramafic rocks and is an important process in modifying melt composition on its way from the source region towards the surface. This experimental study evaluates the compositional variability of tholeiitic basalts upon reaction with depleted peridotite at uppermost-mantle conditions. Infiltration-reaction processes are simulated by employing a three-layered set-up: primitive basaltic powder ('melt layer') is overlain by a 'peridotite layer' and a layer of vitreous carbon spheres ('melt trap'). Melt from the melt layer is forced to move through the peridotite layer into the melt trap. Experiments were conducted at 0.65 and 0.8 GPa in the temperature range 1,170-1,290 degrees C. In this P-T range, representing conditions encountered in the transition zone (thermal boundary layer) between the asthenosphere and the lithosphere underneath oceanic spreading centres, the melt is subjected to fractionation, and the peridotite is partially melting (T (s) similar to 1,260 degrees C). The effect of reaction between melt and peridotite on the melt composition was investigated across each experimental charge. Quenched melts in the peridotite layers display larger compositional variations than melt layer glasses. A difference between glasses in the melt and peridotite layer becomes more important at decreasing temperature through a combination of enrichment in incompatible elements in the melt layer and less efficient diffusive equilibration in the melt phase. At 1,290A degrees C, preferential dissolution of pyroxenes enriches the melt in silica and dilutes it in incompatible elements. Moreover, liquids become increasingly enriched in Cr(2)O(3) at higher temperatures due to the dissolution of spinel. Silica contents of liquids decrease at 1,260 degrees C, whereas incompatible elements start to concentrate in the melt due to increasing levels of crystallization. At the lowest temperatures investigated, increasing alkali contents cause silica to increase as a consequence of reactive fractionation. Pervasive percolation of tholeiitic basalt through an upper-mantle thermal boundary layer can thus impose a high-Si 'low-pressure' signature on MORB. This could explain opx + plag enrichment in shallow plagioclase peridotites and prolonged formation of olivine gabbros.

Combinatorial peptide library-based identification of peptide ligands for tumor-reactive cytolytic T lymphocytes of unknown specificity.

A novel approach for the identification of tumor antigen-derived sequences recognized by CD8(+) cytolytic T lymphocytes (CTL) consists in using synthetic combinatorial peptide libraries. Here we have screened a library composed of 3.1 x 10(11) nonapeptides arranged in a positional scanning format, in a cytotoxicity assay, to search the antigen recognized by melanoma-reactive CTL of unknown specificity. The results of this analysis enabled the identification of several optimal peptide ligands, as most of the individual nonapeptides deduced from the primary screening were efficiently recognized by the CTL. The results of the library screening were also analyzed with a mathematical approach based on a model of independent and additive contribution of individual amino acids to antigen recognition. This biometrical data analysis enabled the retrieval, in public databases, of the native antigenic peptide SSX-2(41-49), whose sequence is highly homologous to the ones deduced from the library screening, among the ones with the highest stimulatory score. These results underline the high predictive value of positional scanning synthetic combinatorial peptide library analysis and encourage its use for the identification of CTL ligands.

No implication of thromboxane-prostanoid receptors in reactive hyperemia of skin skeletal muscle in human forearm

L'hyperhémie réactive, définie comme l'augmentation transitoire du flux sanguin après une courte période d'ischémie, pourrait être influencée par des vasoconstricteurs de la famille des prostanoïdes, telle que la thromboxane. Le terutroban (S18886) est un antagoniste spécifique des récepteurs à la thromboxane. L'étude présentée a cherché à déterminer l'effet du terutroban sur l'hyperhémie réactive dans la peau et le muscle squelettique de l'avant-bras de volontaires sains. Vingt volontaires sains ont été randomisés en aveugle pour recevoir oralement 30mg/j de terutroban ou un placebo pendant 5 jours puis réciproquement pendant une deuxième période de 5 jours, selon un schéma cross-over. L'ischémie transitoire a été provoquée par l'occlusion de l'artère brachiale par une manchette gonflée au dessus de la pression systolique. L'hyperhémie réactive était évaluée dans les tissus de l'avant- bras, en mesurant le flux sanguin, pour la peau par une méthode laser Doppler, et pour le muscle au moyen d'une pléthysmographie par jauge de contrainte durant une occlusion veineuse. Au premier et au dernier jour de chaque période de traitement, l'hyperhémie réactive était mesurée avant et 2 heures après l'ingestion du comprimé. Que ce soit dans la peau ou le muscle, le terutroban n'a pas montré d'effet sur le flux de pic post-occlusion ni sur la réponse globale d'hyperhémie, exprimée en aire sous la courbe. En conclusion, dans la peau et le muscle de sujets sains, l'hypérémie réactive n'est pas influencée par les récepteurs spécifiques à la thromboxane.

Rapid IL-4 production by Leishmania homolog of mammalian RACK1-reactive CD4(+) T cells in resistant mice treated once with anti-IL-12 or -IFN-gamma antibodies at the onset of infection with Leishmania major instructs Th2 cell development, resulting in nonhealing lesions.

Rapid production of IL-4 by Leishmania homolog of mammalian RACK1 (LACK)-reactive CD4(+) T cells expressing the V beta 4-V alpha 8 TCR chains has been shown to drive aberrant Th2 cell development and susceptibility to Leishmania major in BALB/c mice. In contrast, mice from resistant strains fail to express this early IL-4 response. However, administration of either anti-IL-12 or -IFN-gamma at the initiation of infection allows the expression of this early IL-4 response in resistant mice. In this work we show that Leishmania homolog of mammalian RACK1-reactive CD4(+) T cells also expressing the V beta 4-V alpha 8 TCR chains are the source of the early IL-4 response to L. major in resistant mice given anti-IL-12 or -IFN-gamma Abs only at the onset of infection. Strikingly, these cells were found to be required for the reversal of the natural resistance of C57BL/6 mice following a single administration of anti-IL-12 or -IFN-gamma Abs. Together these results suggest that a deficiency in mechanisms capable of down-regulating the early IL-4 response to L. major contributes to the exquisite susceptibility of BALB/c mice to L. major.

Utilité du dosage de la CRP dans le diagnostic, le pronostic et le suivi de la pneumonie acquise dans la communauté [Role of C-reactive protein in the diagnosis, prognosis and follow-up of community-acquired pneumonia].

Community-acquired pneumonia (CAP) is a major clinical problem in terms of morbidity, mortality, and use of hospital resources. It is well recognized that a delay in making the diagnosis and instituting appropriate antibiotic treatment is associated with an increased mortality. C-reactive protein may be helpful in the management of patients with CAP. CRP is widely used in the management of CAP, including diagnosis, prognosis and follow-up. But its usefulness is not known. The aim of this systematic review was to evaluate the usefulness of CRP in the diagnosis, prognosis and follow-up of CAP.

Relation between high-sensitivity C-reactive protein and cardiovascular and renal markers in a middle-income country in the African region.

BACKGROUND: High-sensitivity C-reactive protein (hs-CRP) is associated with several cardiovascular risk factors (CVRF) and with renal function markers. However, these associations have not been examined in populations in the African region. We analyzed the distribution of hs-CRP and the relationship with a broad set of CVRF, renal markers and carotid intima-media thickness (IMT), in the Seychelles (African region). METHODS: We conducted a survey in the population aged 25-64years (n=1255, participation rate: 80.2%). Analyses were restricted to persons of predominantly African descent (n=1011). RESULTS: Mean and median hs-CRP serum concentrations (mg/l) were 3.1 (SD 7.6) and 1.4 (IQR 0.7-2.9) in men and 4.5 (SD 6.7) and 2.2 (IQR 1.0-5.4) in women (p<0.001 for difference between men and women). hs-CRP was significantly associated with several conventional CVRF, and particularly strongly with markers of adiposity. With regards to renal markers, hs-CRP was strongly associated with cystatin C and with microalbuminuria but not with creatinine. hs-CRP was not associated with IMT. CONCLUSIONS: Serum concentration of hs-CRP was significantly associated with sex, several CVRF and selected renal function markers, which extends similar findings in Europe and in North America to a population in the African region. These findings can contribute to guide recommendations for the use of hs-CRP in clinical practice in the region.

Combination of lentivector immunization and low-dose chemotherapy or PD-1/PD-L1 blocking primes self-reactive T cells and induces anti-tumor immunity.

In the last two decades, anti-cancer vaccines have yielded disappointing clinical results despite the fact that high numbers of self/tumor-specific T cells can be elicited in immunized patients. Understanding the reasons behind this lack of efficacy is critical in order to design better treatment regimes. Recombinant lentivectors (rLVs) have been successfully used to induce antigen-specific T cells to foreign or mutated tumor antigens. Here, we show that rLV expressing a murine nonmutated self/tumor antigen efficiently primes large numbers of self/tumor-specific CD8(+) T cells. In spite of the large number of tumor-specific T cells, however, no anti-tumor activity could be measured in a therapeutic setting, in mice vaccinated with rLV. Accumulating evidence shows that, in the presence of malignancies, inhibition of T-cell activity may predominate overstimulation. Analysis of tumor-infiltrating lymphocytes revealed that specific anti-tumor CD8(+) T cells fail to produce cytokines and express high levels of inhibitory receptors such as programmed death (PD)-1. Association of active immunization with chemotherapy or antibodies that block inhibitory pathways often leads to better anti-tumor effects. We show here that combining rLV vaccination with either cyclophosphamide or PD-1 and PD-L1 blocking antibodies enhances rLV vaccination efficacy and improves anti-tumor immunity.

Role of reactive hyperreninemia in blood pressure changes induced by sodium depletion in patients with refractory hypertension

Sixteen patients with refractory hypertension were submitted to vigorous sodium depletion while cardiovascular homeostasis was monitored with measurements of hormonal and hemodynamic parameters and repeat saralasin tests. This regimen resulted in a negative sodium balance by an average of 300 mEq. The loss of sodium closely correlated to the decrease of body weight (r = 0.70, p less than 0.005). Blood pressure (BP) decreased from 176/166 +/- 8/3 to 155/109 +/-6/3 mm Hg. There was a significant correlation between percent increments in plasma renin activity (PRA) and the rise in plasma norepinephrine (r = 0.68, p less than 0.05) and a close negative correlation between percent increase in PRA and the ratio of fall in mean blood pressure (MAP) per unit of weight loss (r = -0.73, p less than 0.005). Thus, patients with the least percent increase in PRA demonstrated the greatest fall in BP per unit of weight loss, indicating that relative rather than absolute elevation of renin may be the factor limiting antihypertensive efficacy of sodium depletion. Sodium depletion induced increase in peripheral resistance and decrease in cardiac output, both mostly attributable to relative hyperreninemia. Indeed, the adverse hemodynamic changes were reversed by angiotensin inhibition, during which BP normalized. It is concluded that vigorous sodium depletion complemented by angiotensin blockade or suppression with sympatholytic agents improves management of otherwise refractory hypertension.