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PubMed1985

Increased plasma concentrations of C9, C1-inhibitor and alpha 1-protease inhibitor associated with cigarette smoking.

The association between various parameters of acute and chronic smoking status and plasma levels of three proteins, C9, C1-inhibitor (C1-INH) and alpha 1-protease inhibitor (alpha 1-PI) were determined for 49 male cigarette smokers and 49 age-matched nonsmokers (mean age = 32.2 years). The mean number of cigarettes smoked was 28.7 per day while the cumulative consumption was only 18.1 pack-years. Plasma levels of all three proteins were significantly higher in the smokers than nonsmokers. Plasma C9 and alpha 1-PI concentrations correlated with cumulative cigarette consumption and plasma nicotine concentrations. While C1-INH concentration did not correlate with either cumulative cigarette consumption or plasma nicotine concentration, it correlated significantly with serum thiocyanate concentration. No consistent correlation was found between plasma concentration of these proteins and parameters of pulmonary function.

Adult↗
PubMed1988

C9 and factor B as acute phase proteins and their diagnostic and prognostic value in disease.

Some components of complement, such as C3, C9 and factor B, behave as acute phase reactants and their serum levels increase significantly in the course of inflammation. The diagnostic and prognostic significance of estimating the serum levels of C9 and factor B was evaluated in patients with Behçet's syndrome, recurrent oral ulceration and Crohn's disease, and the results were compared with those of measuring other acute phase reactants, such as C-reactive protein or alpha 1-antitrypsin. Longitudinal studies in these patients show a clear correlation between clinical indexes of the disease and levels of C9 and factor B. These findings, and experimental studies in monkeys, suggest that inflammation variously affects the synthesis of the acute phase reactants and that they play different roles as mediators of cellular damage.

Acute-Phase Proteins↗
PubMed1993

Involvement of the 20S proteasome in the degradation of ornithine decarboxylase.

Eukaryotic cells have been shown to contain two high-molecular-mass proteases of 700 kDa and 1400 kDa (20S and 26S proteases, respectively). It has been suggested that the 20S protease, also known as proteasome, may constitute the catalytic core of the 26S protease. While the role of the free 20S protease in intracellular protein degradation is unclear, the 26S protease is implicated in the degradation of ubiquinated proteins. We have recently demonstrated, that ornithine decarboxylase (ODC), one of the most labile proteins in mammalian cells, is degraded via an ATP-dependent but ubiquitin-independent proteolytic pathway. Here we extend these observations by demonstrating that in reticulocyte lysate ODC degradation is inhibited by antibodies raised against the C9 subunit of rat proteasome. Partial fractionation of the lysate demonstrated preferential degradation of ODC in the fraction of the lysate proteins that are precipitated by 38% ammonium sulfate. Since it was demonstrated that the 26S protease precipitates at this concentration of ammonium sulfate while the 20S proteasome remains soluble, our results suggest that the 26S protease is the one degrading ODC.

Adenosine Triphosphate↗
PubMed1992

Synteny mapping in the bovine: genes from human chromosome 5.

In an effort to generate a more complete bovine syntenic map of Type I comparative anchor loci, seven homologs to genes found on HSA5 were mapped using a panel of bovine x rodent hybrid somatic cells. Five HSA5 genes, CSF2, RPS14, PDGFRB, FGFA, and CSF1R, were assigned to bovine syntenic group U22 (chromosome 7), while two others, C9 and HGMCR, mapped to U10 and U5, respectively. Previous studies had assigned the HSA5 marker SPARC to bovine syntenic group U22. The mapping of genes spanning the length of HSA5 in cattle and also in mouse permits syntenic comparisons between prototypic genomes of three mammalian orders, providing insight into the evolutionary history of this region of the ancestral mammalian genome.

Acyl Coenzyme A↗
PubMed1975

Trypsin-activated complex of human factor B with cobra venom factor (CVF), cleaving C3 and C5 and generating a lytic factor for unsensitized guinea pig erythrocytes. I. Generation of the activated complex.

A complex formed between cobra venom factor (CVF) and isolated human factor B (B) was found to be converted by trypsin to a stable enzyme, CVF-B which cleaved the third component (C3) and the fifth component (C5) of human complement. The formation of CVF-B by trypsin required divalent cations, whereas the formation of the lytic factor from human serum occurred even in the presence of EDTA. CVF-B purified by gel filtration could initiate the hemolysis of unsensitized guinea pig erythrocytes when incubated with human complement components C5 to C9 in 0.01 M EDTA buffer. C3 was not required for the lysis of guinea pig erythrocytes initiated by CVF-B because of the beta1C precipitation line formed between human serum and anti-beta1C antibody did not inhibit the hemolysis by CVF-B in agarose gel. Treatment of beta1C and beta1F globulins in whole human serum with CVF-B in the presence of 0.01 M EDTA converted them to components with higher mobilities on immunoelectrophoresis.

ABO Blood-Group System↗
PubMed1984

Inhibition of complement-induced [14C]sucrose release by intracellular and extracellular monoclonal antibodies to C9: evidence that C9 is a transmembrane protein.

Monoclonal antibodies to the terminal component of the human complement pathway, C9 were used to inhibit the complement-induced release of entrapped [14C]sucrose from erythrocyte ghosts. Antibodies were present either outside, or entrapped within the ghosts. Different monoclonal antibodies were demonstrated to inhibit [14C]sucrose release depending on whether the antibody was outside or entrapped within the ghosts. These findings demonstrate that C9 within the membrane attack complex on erythrocyte membranes is an asymmetrical transmembrane protein penetrating into the cytoplasmic space.

Animals↗
PubMed1977

Complement system in human colostrum: presence of nine complement components and factors of alternative pathway in human colostrum.

Evidence has been obtained for the presence in human colostrum of all nine components of complement (C), C1 through C9, and factors of the alternative pathway. Samples of colostrums collected from five women at 1-4 days after normal parturition were assayed for the haemolytic activities of individual components. As compared with normal human sera, the activities of each component ranged from 0.03 to 7% of those in sera. The activities of C4, C7 and C9 were relatively high, while that of C1 was extremely low. In most of the cases, the activities of individual components gradually increased following delivery, when expressed as the activity per unit weight (g) of protein in the colostrum. When the colostrums were treated with cobra venom factor, most of the colostrums showed 10-20% reduction in the C3 activity. This finding indicates the presence of factors such as B and D which are involved in the activation of C through the alternative pathway. The role as a defense factor of the C system in human colostrum and milk is discussed in connection with the ability of secretory IgA to react with C.

Colostrum↗
PubMed1987

A double-blind controlled trial of high dose methylprednisolone in patients with multiple sclerosis: 2. Laboratory results.

Laboratory measurements were compared in paired samples from 50 patients included in a double-blind placebo controlled trial of methylprednisolone in the treatment of multiple sclerosis. Cerebrospinal fluid total cell count, IgG and C9 indices, and percentage of peripheral blood OKT8 positive cells were abnormal at entry and returned closer to the normal range after active than placebo treatment, but the differences were not statistically significant. The percentage of peripheral blood OKT4 positive cells was normal at entry as was the amplitude of visual evoked potentials, whereas their latency was prolonged; these measurements were each uninfluenced by methylprednisolone. Corticosteroids might act merely by influencing oedema, but the laboratory results suggest that methylprednisolone affects immunological events which underly rapid onset and recovery of symptoms in patients with multiple sclerosis; additional forms of treatment are needed to maintain these clinical and immunological effects.

Adolescent↗
PubMed1983

Role of the terminal complement pathway in experimental membranous nephropathy in the rabbit.

Our recent observations of a complement-mediated, cell-independent mechanism of altered glomerular permeability in rat membranous nephropathy suggested a possible role for the terminal complement pathway in the mediation of proteinuria in certain forms of glomerular disease. To directly determine whether the membranolytic terminal complement components (C5b-C9) are involved in glomerular injury, we studied the development of proteinuria in normal and C6-deficient (C6D) rabbits, in both of which a membranous nephropathy-like lesion develops early in the course of immunization with cationized bovine serum albumin (cBSA) (pI 8.9-9.2). C6 hemolytic activity of C6D was 0.01% that of control rabbits. After 1 wk of daily intravenous injections of cBSA, proteinuria developed in 71% of controls (median 154, range 1-3,010 mg/24 h, n = 24), whereas none of C6D were proteinuric (median 6, range 2-12 mg/24 h, n = 12, P less than 0.01). After 1 wk of cBSA, both groups had qualitatively identical glomerular deposits of BSA, rabbit IgG, and C3 on immunofluorescence microscopy, predominantly subepithelial electron-dense deposits on electron microscopy, and minimal glomerular inflammatory cell infiltration of glomeruli. Glomeruli were isolated from individual animals after 1 wk of cBSA and deposits of rabbit IgG antibody were quantitated by a standardized in vitro assay using anti-rabbit IgG-125I. Rabbit IgG deposits were found to be similar in control (29.8 +/- 13.2, range 12.7-48.6 micrograms anti-IgG/2,000 glomeruli, n = 6) and C6D rabbits (32.6 +/- 13.8, range 16.8-48.8 micrograms anti-IgG/2,000 glomeruli, n = 5, P greater than 0.05). After 2 wk, coincident with a prominent influx of mononuclear cells and neutrophils, proteinuria developed in C6D rabbits. These results document, for the first time, a requirement for a terminal complement component in the development of immunologic glomerular injury. Since the only known action of C6 is in the assembly of the membrane attack complex, these observations suggest that the membranolytic properties of complement may contribute to glomerular damage.

Animals↗
PubMed1998

Cytokine regulation of the acute-phase protein levels in multiple myeloma.

BACKGROUND: Interleukin (IL) 6 has an important role in the regulation of acute-phase proteins (APPs) during an acute-phase response. We studied IL-6 and other cytokines to determine if they regulate serum APP levels in the same way under the condition of the aberrant, long-lasting 'acute-phase response' that occurs in patients with chronic inflammation and cancer. METHODS: Serum levels of nine positive APPs [CRP, SAA, C1-INH, Bf, C5, C8, C9, alpha 1-acidic glycoprotein (AGP) and haptoglobin] and two negative APPs [transferrin and alpha 2-HS glycoprotein (AHSG)] were measured using immunochemical methods in 59 multiple myeloma patients and in 72 healthy control subjects. Serum IL-6 and tumour necrosis factor (TNF) alpha levels were determined by bioassays. RESULTS: IL-6 was negatively correlated with five out of nine (C1-INH, C8, C9, AGP and haptoglobin) positive APPs but positively correlated with C-reactive protein (CRP). When patients with high and low IL-6 serum concentration were compared, CRP levels were higher, AGP and haptoglobin levels were lower in the high- than in the low-L-6 group, whereas no significant difference between the two groups was found in levels of the other positive and negative APPs. TNF-alpha levels were negatively correlated with transferrin and AHSG levels. No difference in the levels of positive APPs was observed between patients with low and high TNF-alpha serum concentration. By contrast, levels of both transferrin and AHSG were significantly lower in the high- than in the low-TNF-alpha group. CONCLUSIONS: These findings indicate that, except for regulation of the negative APPs by TNF-alpha, the mechanism of APP regulation is different under the conditions of the short-term and the chronic, long-lasting 'acute-phase reaction'.

Acute-Phase Proteins↗
PubMed2024

Value of a secretomic approach for distinguishing patients with COVID-19 viral pneumonia among patients with respiratory distress admitted to intensive care unit.

In intensive care units, COVID-19 viral pneumonia patients (VPP) present symptoms similar to those of other patients with Nonviral infection (NV-ICU). To better manage VPP, it is therefore interesting to better understand the molecular pathophysiology of viral pneumonia and to search for biomarkers that may clarify the diagnosis. The secretome being a set of proteins secreted by cells in response to stimuli represents an opportunity to discover new biomarkers. The objective of this study is to identify the secretomic signatures of VPP with those of NV-ICU. Plasma samples and clinical data from NV-ICU (n = 104), VPP (n = 30) or healthy donors (HD, n = 20) were collected at Nantes Hospital (France) upon admission. Samples were enriched for the low-abundant proteins and analyzed using nontarget mass spectrometry. Specifically deregulated proteins (DEP) in VPP versus NV-ICU were selected. Combinations of 2 to 4 DEPs were established. The differences in secretome profiles of the VPP and NV-ICU groups were highlighted. Forty-one DEPs were specifically identified in VPP compared to NV-ICU. We describe five of the best combinations of 3 proteins (complement component C9, Ficolin-3, Galectin-3-binding protein, Fibrinogen alpha, gamma and beta chain, Proteoglycan 4, Coagulation factor IX and Cdc42 effector protein 4) that show a characteristic receptor function curve with an area under the curve of 95.0%. This study identifies five combinations of candidate biomarkers in VPP compared to NV-ICU that may help distinguish the underlying causal molecular alterations.

Humans↗
PubMed1999

Identification of a 220-kDa membrane tumor-associated antigen by human anti-UK114 monoclonal antibodies selected from the immunoglobulin repertoire of a cancer patient.

Human monoclonal antibodies (HuMAb) specific for a 14-kDa perchloric acid-soluble protein (defined as UK114) were produced by somatic fusion of the human-mouse myeloma K6H6/B5 with Epstein-Barr virus-transformed peripheral B lymphocytes from a cancer patient previously treated with UK101 preparations, containing the UK114 protein. Three IgM-secreting clones were selected on the criteria of specificity for the purified UK114 protein immobilized onto plastic and adapted to grow in a serum-free medium. The reactivity of these antibodies showed a broad distribution pattern restricted to fresh tumor tissues and tumor cell lines, mainly of the adenocarcinoma type. None of the normal cells, nonmalignant cell lines, and normal tissues surrounding the neoplastic lesions were reactive. The immunochemical analysis of the target antigens showed that the HuMAb recognize a molecule of 220 kDa selectively expressed by the surface of tumor cells, as well as a cytoplasmic 14-kDa protein. The 220-kDa antigen was different from other tumor-associated antigens with similar molecular mass and, so far, unique. In the presence of human complement, two of three HuMAb are cytotoxic for tumor cells expressing the 220-kDa surface antigen. The tumor specificity and the lytic ability attributed to these HuMAb are promising features for the exploration of future clinical applications.

Animals↗
PubMed1993

Serum proteins bypass the blood-brain fluid barriers for extracellular entry to the central nervous system.

Extracellular pathways circumventing the mammalian blood-brain fluid barriers (e.g., blood-brain and blood-CSF barriers) have been investigated in the rat by immunohistochemical localization of the endogenous serum proteins albumin, IgG, complement C-9, and IgM and by the exogenous tracer protein horseradish peroxidase (HRP). A demonstrable extracellular pathway into the central nervous system (CNS) is evident at the level of the subarachnoid space/pial surface. Immunoreaction products for the serum proteins and reaction product of intravenously administered HRP are identified over the entire pial surface, in the Virchow-Robin spaces and subpial cortical grey matter, and within phagocytes occupying the subarachnoid space/pial surface and perivascular clefts throughout the CNS. From specific circumventricular organs (e.g., median eminence, area postrema, subfornical organ), well known to lie outside the blood-brain barrier (BBB), each of the blood-borne proteins readily enters adjacent white and grey matter and the ventricular system for subsequent rostrocaudal labeling of the ependymal cell lining. Similar immunohistochemical and blood-borne HRP results are obtained in the CNS of the neonatal rat. Peroxidase delivered into the aorta of postmortem adult rats confirms the presence of a BBB in brain sites containing blood vessels impermeable to blood-borne HRP and the absence of a BBB in sites revealed as leaky to blood-borne HRP in the live rat. The results suggest blood-borne macromolecules, including those of the immune and complement systems, have potential widespread, extracellular distribution within the CNS and cerebrospinal fluid from sites deficient in a BBB (e.g., subarachnoid space/pial surface, circumventricular organs). These observations may have important clinical implications regarding experimental and pathologic autoimmune dysfunction within the CNS and impact on the interpretation of potential transcytosis of blood-borne peptides and proteins through the cerebral endothelium in vivo. A summary diagram of suspected extracellular and intracellular pathways circumventing the blood-brain fluid barriers is provided.

Animals↗
PubMed1990

Measurement of complement activation products in patients with chronic rheumatic diseases.

Measurement of the complement activation products C1s:C1-inh, C3bP and C5b-9 by ELISA in plasma samples from normals, rheumatoid arthritis (RA) and systemic lupus erythematosis (SLE) patients showed significantly elevated levels in the two patient groups (P less than 0.0001 for C1s:C1-inh, C3bP and C5b-9) compared to normals. In seropositive RA patients there were significant correlations between the levels of the three complement activation complexes and IgM-RF, IgG-RF and IgA-RF. However, IgM-RF did not interfere with any of the ELISA systems. Mean levels of C1s:C1-inh, C3bP and C5b-9 were the same in paired plasma and synovial fluids; however, C3bP levels in the paired samples did not correlate with one another by rank. Our conclusions are that: (a) elevated plasma levels of these complement activation products are detectable in rheumatic diseases; (b) plasma levels of these complement activation products are related to Rheumatoid factor (RF) levels in seropositive RA patients; and (c) IgM-RF does not influence these solid-phase ELISA procedures.

Antibodies↗
PubMed1993

Elevation of human cerebrospinal fluid clusterin concentration is associated with acute neuropathology.

Clusterin is a serum glycoprotein which is an inhibitor of complement and is expressed in many tissues in cell injury and death. It has been identified normal and pathological brain tissue and is a component of normal human cerebrospinal fluid (CSF). We have measured the clusterin concentration of 115 abnormal and normal human CSF samples and related these data to the patient's clinical diagnoses. CSF clusterin levels in patients with neurodegenerative and meningeal disease were within the normal range. Twelve of 15 patients with demyelination, however, had significant elevation of CSF clusterin concentration. This was not a specific finding for multiple sclerosis as elevated clusterin levels were also seen in patients with other acute neuropathology. Determination of CSF clusterin concentration may be of clinical value in neurological diagnosis.

Acute Disease↗