Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

For the development of a perfusion culture producing recombinant human protein C, the effects of fetal calf serum and growth factors on cell growth and recombinant protein production were investigated. Although the growth of recombinant cells was stimulated by serum in a dose-dependent manner, a lower concentration of serum (2%) could support both synthesis and post-translational modification of protein C as efficiently as 10% serum. Among the growth factors tested, transferrin enhanced protein C production to the level comparable with 10% serum, while insulin was effective in maintaining cellular metabolism. Based on these results, a perfusion culture for a scale-up production of recombinant protein C was done using an Opticell culture system. A good productivity of the recombinant protein was obtained in low serum or serum-free medium for more than one month.
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PMID:Production of recombinant protein C in serum-containing and serum-free perfusion culture. 136 18

In 71 patients with fever and bacteremia without complications, a prospective study of acute-phase reactants is done. Raises in haptoglobin, ceruloplasmin, alpha-1-antitrypsin, protein C, beta-2-microglobulin, IgA and ferritin serum levels, together with leucocytosis and GSR, were very significant when diagnosis was done. Fibronectin, sideremia and transferrin were lowered. After 3 and 6 days of treatment haptoglobins, alpha-1-antitrypsin, protein C, ferritin, leucocytosis and GSR are lowered, while immunoglobulins, sideremia, transferrin and fibronectin raised, the latter until normalization. Fibronectin as well as changes in iron metabolism were very reliable parameters of inflammation and favorable evolution.
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PMID:[Acute-phase reactants in sepsis]. 148 35

The applications of isoelectric focusing in immobilized pH gradients in clinical chemistry and forensic analysis are reviewed. Strong emphasis is given to the separation of serum proteins, in particular alpha 1-acidic glycoprotein, acid phosphatase, alkaline phosphatase, alpha 1-antitrypsin, apolipoproteins, complement component, factor B, factor XIIIB, group-specific component, lecithin:cholesterol acyltransferase, phosphoglucomutase, prealbumin, protein C and transferrin. The analysis of human parotid salivary proteins is discussed and an assessment is given of the state of the art in thalassaemia screening.
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PMID:Isoelectric focusing in immobilized pH gradients: applications in clinical chemistry and forensic analysis. 193 87

The Ag, pigeon cytochrome c, was coupled to human ferric transferrin by a heteroligation technique to target Ag into the endosomal transport pathway via transferrin receptors. The ability of various types of APC that do or do not express transferrin receptors to process exogenous Ag in their endosomes was investigated by the stimulation of Ag-specific CD4+ T cells with the transferrin-Ag conjugate in a serum-free assay. When two B lymphoma cells were the source of APC, the conjugate was significantly more potent than native Ag in activating the T cells, agreeing with our previous finding using a third B lymphoma cell. The conjugate and Ag were similarly presented by splenic B cells that lack transferrin receptors to the T cells. However, both a macrophage hybridoma and a MHC class II-L cell transfectant hardly elicited a T cell response to the conjugate, although a response to native Ag was readily observed. These findings could not be attributed to an absence of transferrin receptors or receptor-mediated internalization of the conjugate, nor to differential expression of MHC class II molecules or li chain by the APC. The poor presentation of the conjugate by the L cell transfectants was associated with diminished catabolism of the conjugate, however, the macrophage hybridoma rapidly degraded the conjugate, similar to the B lymphoma cell. Peritoneal macrophages, which lack transferrin receptors, and the macrophage hybridoma induced a response to the conjugate only at concentrations that allowed internalization by fluid phase pinocytosis. The lower potency of the conjugate compared with native Ag with non-B-presenting cells suggest that these cell types process the conjugate by a different mechanism than used by B cells. Differences in the mechanism of Ag processing used by APC of distinct cell lineages may possibly influence immune responsiveness.
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PMID:Differences among various lineages of antigen-presenting cells in processing exogenous antigen internalized through transferrin receptors. 790 98

The intraglomerular presence of thrombomodulin (TM) was examined in 19 patients with lupus glomerulonephritis (GN). TM is a cell surface glycoprotein found on endothelial cells and plays a key role in the protein C anticoagulant pathway. Renal biopsy specimens of patients with lupus GN and several kinds of renal disease other than lupus GN, i.e., membranous GN, IgA GN, minimal change nephrotic syndrome (MCNS) and hemolytic uremic syndrome (HUS) were examined by indirect immunofluorescence, using three kinds of monoclonal antibodies against human TM: KA-2, KA-3 and KA-4. It has been reported that KA-3 and KA-4 bind to enzyme-digested TM as well as intact TM, while KA-2 recognizes intact TM only. In the glomeruli from both normal subjects and patients with MCNS, only very weak staining of TM was found. Patients with HUS showed negative TM staining in the glomeruli. In contrast, positive to strongly positive staining of KA-2 as well as of KA-3 and KA-4 was observed mainly along the capillary wall of glomeruli from patients with lupus GN. Some patients with non-lupus GN showed positive staining of these monoclonal antibodies, but the staining was far more intense in most patients with lupus GN than in the patients with non-lupus GN. Staining of albumin and transferrin by the indirect method was negative in all cases of lupus GN that showed positive staining of TM. There was no relationship between the intensity of TM staining and the degree of proteinuria, creatinine clearance or histologic types of lupus GN.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enhanced presence of thrombomodulin in the glomeruli of lupus glomerulonephritis. 802 12

The purpose of the present study was to evaluate the nutritional status of children based on anthropometric measurements, biochemical indicators of protein energy malnutrition as well as hematological variables. The subjects were 93 10- to 12-year-old Bolivian boys: 12 HAHSES, 28 HALSES, 36 LALSES, and 17 LALSES (see Introduction to this Supplement). The overall nutritional status of the boys was evaluated by anthropometric indicators (weight for age [W/A], height for age [H bd, and weight for height [W/H]). The biochemical indicators included proteins total, albumin, prealbumin, orosomucoid and protein C-reactive (for MPE) as well as hematocrit (Ht), hemoglobin (Hb), serum iron, serum ferritin, and transferrin saturation (TS). The prevalence of growth retardation of LSES boys at HA as well as at LA was found to be high when the 3rd percentile was used as the cutoff point. The corresponding prealbumin levels were found to be lower in LSES than in HSES boys at both altitudes. The study shows that LSES boys at both altitudes have significantly lower prealbumin levels than HSES boys. The socioeconomic factor seems to be more critical for the nutritional status of prepubertal boys than altitude. The study also shows that all the boys had hematological parameters within normal range. The HA boys of both SES had higher hemoglobin concentration and hematocrits than the LA boys, a fact that is explained by high-altitude hypoxia. The hematological data do not provide evidence of malnutrition among the boys.
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PMID:Circulating proteins and iron status in blood as indicators of the nutritional status of 10- to 12-year-old Bolivian boys. 805 65

The role of endosomes in exogenous Ag processing was investigated by targeting Ag into the endosomal transport pathway via transferrin receptors. The Ag, pigeon cytochrome c and chicken OVA, were coupled to human ferric transferrin by a heteroligation technique. The conjugates were significantly more efficient than native Ag in stimulating Ag-specific CD4+ T cells, when the APC expressed transferrin receptors. The addition of ferric transferrin eliminated the enhanced response. Paraformaldehyde-fixed APC did not present the conjugates, indicating that the conjugates still required processing to activate T cells. An augmented level of T cell activation was not observed when the APC lacked transferrin receptors or when the conjugate contained the apoenzyme form of transferrin, which does not bind the receptor. The conjugate followed an intracellular pathway similar to that for transferrin, remaining in low density vesicles. Degraded conjugate appeared rapidly in culture supernatants, within 5 min, and peaked by 20 min; under these conditions a T cell response to the conjugate was elicited that was consistent with an early processing compartment. Our results suggest that antigenic peptide fragments can be generated in the early endosomes, without delivery of these Ag to the lysosomes. Thus, various Ag may have differential processing requirements, dictated by their molecular nature, that determine the site of Ag processing.
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PMID:Exogenous antigens internalized through transferrin receptors activate CD4+ T cells. 809 28

The Ag, pigeon cytochrome c, was delivered to the early endosomes in a form coupled to human ferric transferrin that entered APC through transferrin receptors. The processing of the transferrin-Ag conjugate by B lymphoma cells was compared with that of unconjugated native Ag that entered APC by a nonreceptor-mediated mechanism. Within 5 min after internalization, catabolized conjugate was detected in isolated early endosomes and did not accumulate in these organelles. Analysis of the rapid catabolism of the conjugate demonstrated that the Ag, not the transferrin, portion of the molecule was degraded by the APC, suggesting that similar proteases may mediate the processing of the conjugate and native Ag. The processing mechanisms of these molecules shared similarities. Treatment of APC with chloroquine or paraformaldehyde interfered with the stimulation of Ag-specific CD4+ T cells by both transferrin-Ag conjugate and native Ag. However, the T cell responses to the conjugate and native Ag were different in two important respects. First, T cell activation by the conjugate began at an earlier time point and occurred at a faster rate than T cell stimulation by the same concentration of native Ag during a 3-h time course. Second, the T cell response to the conjugate, but not to native Ag, was diminished by treating APC with cycloheximide, a reversible protein synthesis inhibitor. This partial inhibition of the conjugate response by cycloheximide could not be attributed to significant effects on transferrin receptor expression, or on internalization, recycling, or degradation of the conjugate. The differential cycloheximide-sensitivity of the T cell responses indicates that the processing pathways of the two molecules are different. Our findings suggest that the early endosomes may function as an Ag-processing compartment, and that more than one pathway may lead to productive processing in B lymphoma cells.
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PMID:Antigen presentation by B lymphoma cells. Requirements for processing of exogenous antigen internalized through transferrin receptors. 840 20

HLA-DM- APC are unable to present soluble Ags to T cells in the context of class II DR molecules. This defect in DM- APC can be overcome by receptor-mediated delivery of Ag into cells. Ag conjugated to ligands for cell surface receptors, such as transferrin or goat anti-human Ig, was processed and presented by DM- T2.DR4 cells. Intracellular processing of Ag conjugates was required, as receptor cross-linking alone did not restore presentation by DM- APC. Ag conjugates targeted by transferrin receptors to endosomes or via surface Ig to endosomal and lysosomal compartments, were each efficiently presented by DM- cells. These Ag conjugates were predominantly localized in light density endosomes in T2.DR4 cells. This study demonstrates that the facilitated uptake and sorting of exogenous Ag by cell surface receptors allow efficient class II-restricted presentation even in the absence of HLA-DM.
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PMID:Receptor-mediated endocytosis of antigens overcomes the requirement for HLA-DM in class II-restricted antigen presentation. 897 67

Carbohydrate-deficient glycoprotein syndrome type 1A (CDGS1A) is an inherited disorder with multisystemic abnormalities resulting from failure to generate sufficient lipid-linked oligosaccharide precursor or to transfer the sugar chain to many glycoproteins. Cultured fibroblasts from these patients have reduced incorporation of mannose into glycoproteins which can be corrected by adding D-mannose to the culture medium. Providing dietary mannose to elevate mannose concentrations in vivo therefore might remedy some of the underglycosylation in the patients. Five children with CDGS1A aged 15 months to 14 y completed a protocol of enteral supplementation with D-mannose 100 mg/kg every 3 h for 9 d. The mean S-mannose level increased from 32 microM (range 22-42 microM) to a trough value of 72 microM (range 39-103 microM). No serious side effects were observed. Surprisingly, the mean serum concentration of four glycoproteins (transferrin, alpha1-antitrypsin, antithrombin, and thyroxine-binding globulin) tended to decrease, and the mean serum concentration of carbohydrate-deficient transferrin (CDT) increased. Furthermore, the initially present abnormal isoforms of these glycoproteins and of protein C became more prominent and/or additional abnormal isoforms appeared. This short-term trial does not support a benefit of mannose to the deficient glycosylation of CDGS1A patients.
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PMID:Failure of short-term mannose therapy of patients with carbohydrate-deficient glycoprotein syndrome type 1A. 973 38


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