Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunofluorescent staining of cytoplasmic IgM (heavy chains) and CD24 as well as their simultaneous staining with surface B cell markers was used to study immunophenotype changes in B cell differentiation. Human hematopoietic B cell lines P3HR1 and RAJI were used. We found that IgM and CD24 cell markers while absent on cell membrane could be detected in their cytoplasm (c). The presence of cIgM in cell lines RAJI, P3HRI indicates their early pre-B differentiation stage. The presence of cCD24 simultaneously with mCD22 and cIgM is the evidence that hematopoietic cell lines or leukemias may not accurately reflect normal differentiation pathway. Combinations of cIgM, cCD24 with surface B cell markers CD10, CD19 on these cell lines can be considered as leukemia associated phenotypes. Some of them were shown in bone marrow and peripheral blood of pre-B ALL and B-CLL patients and can be used for the detection of minimal residual disease. Different fixation/permeabilization methods were tested in order to choose the optimal one for simple detection of cytoplasmic markers or their simultaneous detection with surface markers by flow cytometry. They included "one-component-methods" (methanol-M, saponin-S), methods combining these components with paraformaldehyde (P+M, P+S) or buffered formaldehyde acetone (BFA). The choice depended on individual marker detected. General parameters like the proportion of debris, cell aggregation, cell loss and the changes of scatter parameters FSC and SSC were taken into consideration. The priorities of combined methods P+S, P+M1 and BFA over one-component methods are demonstrated.
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PMID:Some early differentiation markers detected in cytoplasm of pre-B cells by flow cytometry. 899 61

To facilitate the analysis of immunolabelled peripheral blood or bone marrow leucocytes by flow cytometry, a number of reagents are available commercially that lyse erythrocytes and fix leucocytes. This study has investigated the effect on antibody-labelled whole blood of the Q-Prep procedure, in which erythrocytes are lysed with formic acid, and leucocytes are fixed with formaldehyde. Whole blood samples were labelled with the nuclear dye LDS-751 and with antibodies to HLA-DR or belonging to CD2, CD3, CD4, CD7, CD8, CD10, CD13, CD14, CD19, CD20, CD29, CD33, CD45, CD45RA, CD56, and CD62L (TQ-1) that were directly conjugated to either phycoerythrin (PE) and/or fluorescein isothiocyanate (FITC). Leucocytes were analysed by flow cytometry either in unfixed, unlysed whole blood (15) or after preparation using the Q-Prep system. The binding of eight antibodies, CD19-FITC, CD2-PE, CD3-PE, CD4-PE, CD19-PE, CD29-PE, CD45RA-PE, and CD56-PE, to the surface of lymphocytes was reduced, resulting in significant changes (P < 0.05) in the percentages of cells that stained positively and/or their mean molecules of equivalent fluorochrome (MEF). Further analysis revealed that this was due to the formic acid used during the erythrocyte lysis stage.
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PMID:The Q-Prep system: effects on the apparent expression of leucocyte cell surface antigens. 914 13

Processing of human proinsulin C-peptide and its C-terminal pentapeptide in blood serum was studied using reverse-phase HPLC and electrospray mass spectrometry. The results reveal degradation of both peptides, with a longer half-life for intact C-peptide than for the C-terminal pentapeptide. Products from C-peptide degradation were not distinguishable from the peptide background, suggesting endopeptidase degradation of C-peptide. In contrast, a set of products from the C-terminal pentapeptide were identifiable and corresponded to successive losses from the N terminus, showing that the pentapeptide is degraded by aminopeptidase in serum. Consistent with this finding, a slower degradation was found for the N-acetyl-protected pentapeptide. Removal of serum proteins by acetone precipitation produced N-terminally carbamate-modified C-peptide via a Schiff base intermediate (a ketimine with acetone), to which CO(2) was added and acetone removed, generating a cyclic side chain via anhydride formation. The modification was not seen with the pyroglutamate form of C-peptide, with the N-terminally acetylated C-peptide, or with a control peptide having N-terminal Phe, but was found with human C-peptide, its N-terminal tetrapeptide, and a rat C-peptide fragment (all with N-terminal Glu). Hence, the modification appears to require N-terminal Glu, but this is not the only prerequisite since the C-terminal pentapeptide and another control peptide (also starting with Glu) were not modified. A peptide aldimine Schiff base leading to CO(2) incorporation was detected with formaldehyde in NaHCO(3). The observation that C-peptide forms Schiff bases with ketones/aldehydes, enhancing covalent attachment of CO(2), may have biological implications.
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PMID:Proinsulin C-peptide and its C-terminal pentapeptide: degradation in human serum and Schiff base formation with subsequent CO2 incorporation. 1282 90

The light chain of tetanus neurotoxin (TeNT) is a zinc-dependent metalloprotease which specifically cleaves the synaptic vesicle protein synaptobrevin. This crucial mechanism of tetanus toxicity leads to a blockade of inhibitory neurotransmitter release. We recently reported the development of a highly sensitive endopeptidase assay for the specific in vitro detection of active TeNT based on this proteolytic feature. Using this method, we could show that formaldehyde-inactivated TeNT preparations (toxoids), which are used for the production of tetanus vaccines, contain a high residual synaptobrevin-cleaving activity. Such an activity was detected in numerous tetanus toxoid batches obtained from several vaccine manufacturers which did not display any in vivo toxicity in the obligatory animal tests. The enzymatic activity could be attributed to the presence of free TeNT light chains whose function had not been restrained by the formaldehyde treatment, but which lack the functional heavy chain necessary for entering neurons in vivo. To our knowledge, this is the first report describing a residual proteolytic activity in tetanus toxoids.
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PMID:Residual enzymatic activity of the tetanus toxin light chain present in tetanus toxoid batches used for vaccine production. 1855 57

The action of a botulinum neurotoxin (BoNT) commences by binding at the nerve terminal via its H- (heavy) chain to a cell-surface receptor, which consists of a ganglioside and a cell-surface protein. Binding enables the L-chain, a Zn2+-dependent endopeptidase, to be internalized and act intracellularly, cleaving one or more SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins required for vesicle docking and fusion, which results in reduced neurotransmitter release. Sprouts emerge at motor-nerve terminals that reestablish synaptic contact and lead to restoration of exocytosis. As the terminals recover, sprouts retreat and synaptic function is fully re-established. Neutralizing antibodies (Abs) induced by vaccination can prevent the neuronal changes produced by BoNT. Until recently, vaccines against BoNT have been based on toxins inactivated by treatment with formaldehyde (toxoids) and contain either one (monovalent) or five (pentavalent) toxoids, but formalin-based toxoids have many undesirable side effects. Availability of the gene sequences of BoNT serotypes enabled design of recombinant subunit vaccines that have included the C-terminal domain of the H chain (HC, its subdomains (HC-N and HC-C), the L- (catalytic) chain, and the L-chain expressed with the translocation domain (LCHN). Of these, the HC displays the highest protective ability. Recent vaccines have used whole toxins inactivated by three key mutations at the enzyme active site, which have been found to be very effective in mice against the correlated toxin. Immune responses to BoNTs A and B epitopes are under the hosts MHC (major histocompatibility complex) control. Anti-BoNT/A blocking Abs bind at sites that coincide or overlap with those that bind synaptosomes and to BoNT/B at sites that overlap with synaptotagmin-II and ganglioside-binding sites. Therefore, locations occupied by blocking Abs preclude the respective toxin from binding to its receptor and thus from binding to cell surface. Information on BoNT epitopes for blocking Abs, sites for binding to cell surface receptors, and T-cell epitopes that provide help to B cells making blocking Abs afford a prospect for rational design of stable synthetic vaccines. These constructs should be clinically useful for epitope-selective modulation of Ab responses to restore effective BoNT treatment in immunoresistant patients.
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PMID:Mode of action of botulinum neurotoxins: current vaccination strategies and molecular immune recognition. 2037 Jun 28