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Specific Peptides (specific + peptide)
Selected AbstractsElastin-derived peptides: Matrikines critical for glioblastoma cell aggressiveness in a 3-D systemGLIA, Issue 16 2009Bérénice Coquerel Abstract In the most common primary brain tumors, malignant glioma cells invade the extracellular matrix (ECM) and proliferate rapidly in the cerebral tissue, which is mainly composed of hyaluronan (HA) along with the elastin present in the basement membrane of blood vessels. To determine the role of ECM components in the invasive capacity of glioma cell lines, we developed a 3-D cell-culture system, based on a hydrogel in which HA can be coreticulated with kappa-elastin (HA-,E). Using this system, the invasiveness of cells from four glioma cell lines was dramatically increased by the presence of ,E and a related, specific peptide (VGVAPG)3. In addition, MMP-2 secretion increased and MMP-12 synthesis occurred. Extracellular injections of ,E or (VGVAPG)3 provoked a pronounced and dose-dependent increase in [Ca2+]i. ,E significantly enhanced the expression of the genes encoding elastin-receptor and tropoelastin. We propose the existence of a positive feedback loop in which degradation of elastin generates fragments that stimulate synthesis of tropoelastin followed by further degradation as well as migration and proliferation of the very cells responsible for degradation. All steps in this ECM-based loop could be blocked by the addition of either of the EBP antagonists, lactose, and V-14 peptide, suggesting that the loop itself should be considered as a new therapeutic target. © 2009 Wiley-Liss, Inc. [source] Current HIV-2 diagnostic strategy overestimates HIV-2 prevalence in China,JOURNAL OF MEDICAL VIROLOGY, Issue 5 2009Maofeng Qiu Abstract A significant number of HIV-2 infections have been reported in China using Western blot as per current guidelines for HIV-2 diagnosis in China. However, most specimens were also positive on HIV-1 Western blot suggesting cross-reactivity and possible overestimation. We carried out the current study to evaluate a strategy to diagnose the HIV-2 infections in China. A total of 119 specimens received from 16 provinces were likely to be HIV-2 when tested according to current guidelines in China using the Genelabs Western blot (HIV Blot 2.2 WB). Further testing by HIV-2 WB (Bio-Rad New LAV Blot II or Genelabs HIV Blot 1.2 WB) scored 56 (47.1%) of 119 samples with banding pattern suggestive of HIV-2 infection, and 63 (52.9%) were HIV-2 indeterminate. A peptide-based HIV-1 and HIV-2 enzyme immunoassay for differential diagnosis of HIV-1 and HIV-2 infections was validated and used. This in-house EIA demonstrated that only 1 (0.8%) of 119 specimens had HIV-2 specific antibodies, while 2 (1.7%) were dually reactive. These results were highly concordant (>99%) with those by Inno-LIA HIV-I/II (Innogenetics, Belgium), which also use specific peptides for type-specific diagnosis. Our data demonstrates that HIV-2 infection is rare in China, and HIV-2 Western blot may overestimate the prevalence of HIV-2 in the population with HIV-1. The HIV-2 diagnostic strategy in China needs to be revised to include more specific peptide-based immunoassays. J. Med. Virol. 81:790,797, 2009. © 2009 Wiley-Liss, Inc. [source] HLA-DR-restricted T-cell responses to factor VIII epitopes in a mild haemophilia A family with missense substitution A2201PHAEMOPHILIA, Issue 102 2010R. A. ETTINGER Summary., An HLA-DRA-DRB1*0101-restricted T-cell epitope in the factor VIII (FVIII) C2 domain occurred in a mild haemophilia A patient with missense substitution FVIII-A2201P. His T cells responded to synthetic peptides FVIII2186,2205 and FVIII2194,2213 (J Thromb Haemost 2007; 5: 2399). T cells from family members with genotype FVIII-A2201P were analysed to determine if FVIII-specific T cells occur in individuals with a haemophilic mutation but no clinically significant inhibitor response. Fluorescent MHC class II tetramers corresponding to subjects'HLA-DRB1 types were loaded with 20-mer peptides and utilized to label antigen-specific CD4+ T cells. T-cell responses to peptides spanning the FVIII-C2 sequence were evaluated. T cells recognizing specific peptides were cloned, and antigen specificity was verified by proliferation assays. Plasma and/or purified IgG samples were tested for FVIII inhibitory activity. CD4+ T cells and T-cell clones from two brothers who shared the DRB1*0101 allele responded to FVIII2194,2213. A haemophilic cousin's HLA-DRA-DRB1*1104-restricted response to FVIII2202,2221 was detected only when CD4+CD25+ cells were depleted. A great uncle and two obligate carriers had no detectable FVIII-C2-specific T cells. Concentrated IgG from the brother without a clinical inhibitor response showed a low-titre FVIII inhibitor. FVIII-specific T cells and inhibitory IgG were found in a previously infused, haemophilic subject who had a sub-clinical FVIII inhibitor. CD4+CD25+ depleted T cells from a non-infused haemophilic cousin recognized an overlapping FVIII epitope, indicating a latent HLA-DRA-DRB1*1104-restricted T-cell response to FVIII. Specific T-cell responses to FVIII can occur without clinically significant inhibitors. [source] High-sensitivity analysis of specific peptides in complex samples by selected MS/MS ion monitoring and linear ion trap mass spectrometry: Application to biological studiesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2007Inmaculada Jorge Abstract Mass spectrometry (MS) is a technique of paramount importance in Proteomics, and developments in this field have been possible owing to novel MS instrumentation, experimental strategies, and bioinformatics tools. Today it is possible to identify and determine relative expression levels of thousands of proteins in a biological system by MS analysis of peptides produced by proteolytic digestion. In some situations, however, the precise characterization of a particular peptide species in a very complex peptide mixture is needed. While single-fragment ion-based scanning modes such as selected ion reaction monitoring (SIRM) or consecutive reaction monitoring (CRM) may be highly sensitive, they do not produce MS/MS information and their actual specificity must be determined in advance, a prerequisite that is not usually met in a basic research context. In such cases, the MS detector may be programmed to perform continuous MS/MS spectra on the peptide ion of interest in order to obtain structural information. This selected MS/MS ion monitoring (SMIM) mode has a number of advantages that are fully exploited by MS detectors that, like the linear ion trap, are characterized by high scanning speeds. In this work, we show some applications of this technique in the context of biological studies. These results were obtained by selecting an appropriate combination of scans according to the purpose of each one of these research scenarios. They include highly specific identification of proteins present in low amounts, characterization and relative quantification of post-translational modifications such as phosphorylation and S -nitrosylation and species-specific peptide identification. Copyright © 2007 John Wiley & Sons, Ltd. [source] Current HIV-2 diagnostic strategy overestimates HIV-2 prevalence in China,JOURNAL OF MEDICAL VIROLOGY, Issue 5 2009Maofeng Qiu Abstract A significant number of HIV-2 infections have been reported in China using Western blot as per current guidelines for HIV-2 diagnosis in China. However, most specimens were also positive on HIV-1 Western blot suggesting cross-reactivity and possible overestimation. We carried out the current study to evaluate a strategy to diagnose the HIV-2 infections in China. A total of 119 specimens received from 16 provinces were likely to be HIV-2 when tested according to current guidelines in China using the Genelabs Western blot (HIV Blot 2.2 WB). Further testing by HIV-2 WB (Bio-Rad New LAV Blot II or Genelabs HIV Blot 1.2 WB) scored 56 (47.1%) of 119 samples with banding pattern suggestive of HIV-2 infection, and 63 (52.9%) were HIV-2 indeterminate. A peptide-based HIV-1 and HIV-2 enzyme immunoassay for differential diagnosis of HIV-1 and HIV-2 infections was validated and used. This in-house EIA demonstrated that only 1 (0.8%) of 119 specimens had HIV-2 specific antibodies, while 2 (1.7%) were dually reactive. These results were highly concordant (>99%) with those by Inno-LIA HIV-I/II (Innogenetics, Belgium), which also use specific peptides for type-specific diagnosis. Our data demonstrates that HIV-2 infection is rare in China, and HIV-2 Western blot may overestimate the prevalence of HIV-2 in the population with HIV-1. The HIV-2 diagnostic strategy in China needs to be revised to include more specific peptide-based immunoassays. J. Med. Virol. 81:790,797, 2009. © 2009 Wiley-Liss, Inc. [source] Differentiation among various kinds of cheese by identification of casein using HPLC-chip/MS/MS,JOURNAL OF SEPARATION SCIENCE, JSS, Issue 16 2010Martin Franc Abstract In proteomics, proteins can be identified by enzymatic cleavage of the target protein using an enzyme of the known specificity (primarily trypsin), sequencing the obtained specific peptides by MS and comparing the amino acid sequence of the peptides with a protein database. The sophisticated approach described above was used in this study to determine and verify the original species of cheeses. Proteins were extracted from three different cheese samples which were produced from cow, sheep and goat milks. The isolated proteins were cleaved with trypsin and the peptides obtained were sequenced and identified by a HPLC-chip/MS/MS microfluidic system. Two different extraction methods and two various chromatographic sorbents packed in plastic chips were studied. ,-Lactoglobuline and four kinds of casein were found in the cheese samples. The species of ,-casein were identified unambiguously in all the three cheese samples and, thus, ,-casein can be used to determine the origin of milk of the cheese. The other proteins found in the samples show very similar primary structures and cannot be recommended for identification of the cheese milk origin. [source] Bioaffinity magnetic reactor for peptide digestion followed by analysis using bottom-up shotgun proteomics strategyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2008Lucie Korecká Abstract We report an efficient and streamlined way to improve the analysis and identification of peptides and proteins in complex mixtures of soluble proteins, cell lysates, etc. By using the shotgun proteomics methodology combined with bioaffinity purification we can remove or minimize the interference contamination of a complex tryptic digest and so avoid the time-consuming separation steps before the final MS analysis. We have proved that by means of enzymatic fragmentation (endoproteinases with Arg-C or/and Lys-C specificity) connected with the isolation of specific peptides we can obtain a simplified peptide mixture for easier identification of the entire protein. A new bioaffinity sorbent was developed for this purpose. Anhydrotrypsin (AHT), an inactive form of trypsin with an affinity for peptides with arginine (Arg) or lysine (Lys) at the C-terminus, was immobilized onto micro/nanoparticles with superparamagnetic properties (silica magnetite particles (SiMAG),Carboxyl, Chemicell, Germany). This AHT carrier with a determined binding capacity (26.8 nmol/mg of carrier) was tested with a model peptide, human neurotensin, and the resulting MS spectra confirmed the validity of this approach. [source] Investigation of proteins and peptides from yeastolate and subsequent impurity testing of drug productBIOTECHNOLOGY PROGRESS, Issue 2 2009Lawrence W. Dick Jr. Abstract Hydrolysates play an important role in modern biological production. These mixtures are mostly undefined and contain a mixture of proteins, peptides, and amino acids along with other non,amino acid-based components. Recently, there has been an interest in defining and sequencing proteins and peptides in these hydrolysates to subsequently develop an assay to ensure removal during product purification. This work investigates an ultrafiltrate of yeastolate to determine whether any protein is present. Size exclusion chromatography indicated a possible high molecular weight component (>10 kDa). This suspected high molecular weight fraction was collected and investigated. It was determined that this fraction consists of nucleic acids; and no protein was detected using sensitive modern techniques including HPLC, mass spectrometry, and SDS-PAGE. Next, five unique, yeast-specific peptides were identified, sequenced, and confirmed. Finally, an impurity assay for any residual yeast specific peptides was developed and the analytical metrics were determined including accuracy, precision, linearity, range, and limits of detection and quantitation. © 2009 American Institute of Chemical Engineers Biotechnol. 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