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Biomedical subjects

G Soe

Publications and source records attributed to G Soe.

At least 19 recordsLinked to original sources

A monoclonal antibody specific to the granulocyte-derived elastase-fragment D species of human fibrinogen and fibrin: its application to the measurement of granulocyte-derived elastase digests in plasma.

When granulocytes are stimulated under certain clinical conditions, elastase is released therefrom and digests fibrin(ogen) independently of the plasmin system, which may also be mobilized simultaneously. Thus, discrimination of these 2 systems becomes urgent for the diagnosis and treatment of the underlying diseases. Using as immunogen a 97-kd granulocyte-elastase digest of human fibrinogen, we raised an antibody IF-123 that specifically recognizes elastase digests of human fibrin(ogen). The 97-kd elastase fragment resembles plasmic fragment D(1), and the epitope of this antibody is located on the Aalpha (196-204) residue segment. This segment appears to be masked in fibrin(ogen) but exposed when the Aalpha Leu 204-Ile 205 peptide bond is cleaved by elastase. Cathepsin G concomitantly released from granulocytes failed to expose the epitope. By an enzyme immunoassay using IF-123 as the capture antibody, the elastase digests of fibrin(ogen) can be measured in plasma samples without interference by abundantly coexisting fibrinogen. Indeed, we found that the elastase digests were mostly elevated in patients with inflammation or malignant tumors, but remained in a normal range in patients with a benign gastrointestinal tract disease such as duodenal ulcer and polyps in the gallbladder or the colon. Like the plasmic D-dimer, the elastase digests predominantly consisted of the DD/E complex and DD/E-containing high-molecular weight derivatives apparently corresponding to the phase-3 plasmic digests of cross-linked fibrin. (Blood. 2000;95:1721-1728)

Amino Acid Sequence↗

Monoclonal antibody specific for tissue factor pathway inhibitor-factor Xa complex: its characterization and application to plasmas from patients with disseminated intravascular coagulation and pre-disseminated intravascular coagulation.

Tissue factor pathway inhibitor (TFPI), a Kunitz-type protease inhibitor with three tandem inhibitory domains (K1, K2 and K3), inhibits the initial reactions of the extrinsic blood coagulation pathway through its K1 and K2 domains. We prepared and characterized a monoclonal antibody (Mab8-1) against TFPI-factor Xa (TFPI-Xa) complex. The reactivities of Mab8-1 toward TFPI-Xa complex, TFPI without C-terminal (TFPI-C)-Xa complex, K1K2-Xa complex and K2K3-Xa complex were examined using a surface plasmon resonance analysis (Biacore). The Biacore system allowed a quantitative analysis of antibody-antigen interaction, in real time, from which the association and dissociation rate constants could readily be obtained. The bindings of Mab8-1 to TFPI-Xa complex, TFPI-C-Xa complex and K2K3-Xa complex were each concentration-dependent. However, no binding of Mab8-1 to the K1K2-Xa complex was observed. The binding of Mab8-1 to TFPI or Xa was also not observed. These results suggested that the epitope for Mab8-1 was exposed in the K3 domain of TFPI, which was generated by the conformational change after the formation of TFPI-Xa complex. We then developed an enzyme-linked immunosorbent assay method specific for TFPI-Xa complex using Mab8-1, and we used this assay to measure plasma levels of TFPI-Xa. The normal range assessed from analyses of plasma from 30 normal healthy volunteers was 17.7-66.7 with a mean of 35.5 +/- 11.7 pmol/l. In order to asses the clinical implication of TFPI-Xa complex in the plasma of patients with thrombotic disorders, plasma concentrations were measured in 37 patients with disseminated intravascular coagulation (DIC) caused by a variety of underlying diseases. The TFPI-Xa antigen levels were significantly higher in the patients with DIC (51.9 +/- 21.6 pmol/l) and the 36 patients with pre-DIC (55.1 +/- 20.2 pmol/l) than in the 137 non-DIC patients (37.9 +/- 13.1 pmol/l). In the patients with DIC or pre-DIC, there was no significant correlation between TFPI-Xa complex and the elevated levels of thrombin-antithrombin complex, plasmin-alpha2 plasmin inhibitor complex, D-dimer, soluble fibrin monomer, soluble thrombomodulin or tissue factor. These data indicate that the plasma level of TFPI-Xa seems to be a novel independent molecular marker of DIC and pre-DIC.

Antibodies, Monoclonal↗

Fibroblasts spread on immobilized fibrin monomer by mobilizing a beta1-class integrin, together with a vitronectin receptor alphavbeta3 on their surface.

Human and murine fibroblasts were found to spread far more avidly on fibrin monomer monolayers than on immobilized fibrinogen, indicating that removal of fibrinopeptides by thrombin is a prerequisite for the fibrin-mediated augmentation of cell spreading. In fact, cell spreading was not efficiently augmented on monolayers of a thrombin-treated dysfibrinogen lacking the release of fibrinopeptide A due to an Aalpha Arg-16 --> Cys substitution. Since a synthetic Arg-Gly-Asp (RGD)-containing peptide inhibited the fibrin-mediated cell spreading, subsequent dissociation of the carboxyl-terminal globular domain of the Aalpha-chains appears to render the RGD segments accessible to the cell-surface integrins. In support of this, fibrin-augmented cell spreading was inhibited by an antibody recognizing a 12-kDa peptide segment with gamma Met-89 at its amino terminus, which is located in close association with the RGD segment at Aalpha 95-97 in the helical coiled-coil interdomainal connector. The fibrin-mediated augmentation of cell spreading was inhibited not only by an antibody against human vitronectin receptor (LM 609) but also by an antibody against the beta1 subunit of integrin (mAb13), suggesting that the beta1-class integrin together with a vitronectin receptor, alphavbeta3, is mobilized onto the surface of fibroblasts upon contact with the fibrin monomer monolayer.

Animals↗

A monoclonal antibody that recognizes a neo-antigen exposed in the E domain of fibrin monomer complexed with fibrinogen or its derivatives: its application to the measurement of soluble fibrin in plasma.

Using urea-solubilized human fibrin monomer as an immunogen, we raised in mice a battery of monoclonal antibodies that reacted with the immunogen but not with urea-treated or native fibrinogen. Although they all failed to react with acid-solubilized fibrin monomer (acid-FM) alone, an antibody designated as IF-43 was found to recognize acid-FM, which was bound with fibrinogen or its derivatives to form a 1:2 complex of soluble fibrin. The epitope for this antibody, thus, appears to be exposed most probably by conformation changes induced in the acid-FM molecule upon formation of the complex. Because IF-43 was able to recognize fibrin-derived plasmic fragment E treated with urea but not the thrombin- and urea-treated amino-terminal disulfide knot of fibrinogen, the presence of the A alpha (52-78) residue segment seems to be prerequiste for the epitope expression. The antibody was found to react with soluble fibrin monomer spiked to normal plasma dose-dependently up to 200 micrograms/mL. By an aggregation assay using latex beads coated with IF-43, we found that concentrations of soluble fibrin monomer in plasma derived from patients with thrombotic diseases were mostly elevated, but not necessarily correlated with those of the D-dimer, reflecting another aspects of the disease. Furthermore, the soluble fibrin monomer in plasma derived from patients with thrombotic diseases was found to be depleted solely of the A peptides, but not the B peptides, based on its subunit polypeptide compositions lacking the beta-chain on immunoblotting.

Animals↗

An alternative elastase-mediated degradation of fibrinogen and fibrin observed in a patient with herpes simplex encephalitis and pneumonia.

A 74-year-old female developed pneumonia following herpes simplex encephalitis. Her white blood cell counts reached 28,400/microliters, about 90% of which consisted of granulocytes. The polymorphonuclear (PMN) elastase/alpha 1-antitrypsin complex levels increased and reached the maximum of 5,019 ng/ml, indicating the release of a large amount of elastase derived from the granulocytes. The mechanism of PMN elastase release was most likely to be granulocyte destruction associated with phagocytosis. The cleavage of fibrinogen and fibrin by PMN elastase, independent of plasmin, was indicated by the presence of the fragments in immunoprecipitated plasma from the patient corresponding to elastase-induced FDP D and DD fragments and the absence of fragments corresponding to plasmin-induced FDP D and DD fragments on SDS-PAGE. These findings suggested that the large amount of PMN elastase released from the excessive numbers of granulocytes in this patient with herpes simplex encephalitis and pneumonia, induced the cleavage of fibrinogen and fibrin without the participation of plasmin.

Aged↗

A rapid latex immunoassay for the detection of plasmin-alpha 2-plasmin inhibitor complex. Utilization of two monoclonal antibodies differentially recognizing respective components of the complex.

Among six monoclonal antibodies raised against the human plasmin-alpha 2-plasmin inhibitor complex (PPI), three antibodies were found to recognize the plasmin part (group 1) and another three the alpha 2-plasmin inhibitor (alpha 2-PI) part (group 2) of the complex. One of the group-1 monoclonal antibodies, designated JIPPI-3, specifically reacted with a segment of plasmin containing kringles 2 and 3. Although all three group 2 antibodies reacted with both alpha 2-PI and PPI on immunoblotting and ELISA, one of them, JIPPI-50, was unable to react with alpha 2-PI, when the antibody had been covalently conjugated to Sepharose 4B gels and tested for reactivity against the antigens in solution. The results indicated that the epitope for this antibody had been buried in nascent alpha 2-PI, but had been exposed by complex formation with plasmin or by possible conformational changes induced in the alpha 2-PI molecule on insolubilization to nitrocellulose membranes or immunoplates. By utilizing a set of JIPPI-3 and JIPPI-50, individually coated onto latex beads, PPI could be measured in plasma in the range of 0.8-100 micrograms/ml without interference by coexisting plasminogen (120-200 micrograms/ml) or alpha 2-PI (70 micrograms/ml). This measurable range seems to cover the level of PPI clinically observed under hyperfibrinolytic states.

Animals↗

Calcium ion-dependent monoclonal antibody against human fibrinogen: preparation, characterization, and application to fibrinogen purification.

We have produced a high-affinity monoclonal antibody classified as IgG1 with kappa-type light chains that recognizes the calcium ion(Ca2+)-dependent conformation of the D-domain of human fibrinogen. Binding of fibrinogen in solution to the insolubilized antibody increased in the presence of increasing concentrations of up to 2 mM Ca2+, the half-maximal binding being reached at 130 microM Ca2+. The dissociation constant was estimated to be 1.6 x 10(-8) M at 2 mM Ca2+. The antibody was found also to be dependent on other divalent metal ions including Zn2+, Mn2+, Co2+ and Cu2+, but not Ba2+, Mg2+ or Sr2+. The synthetic Gly-Pro-Arg-Pro-amide peptide, which has recently been shown to bind to close proximity to the calcium binding site in the D-domain, was unable to elicit the conformation for the antigen to be recognized by this antibody. This antibody was found to be a suitable ligand for the immunoaffinity chromatography of normal and abnormal fibrinogens directly from citrated plasma depleted of the vitamin K-dependent proteins or heparinized plasma by eliminating the precipitation procedure widely adopted in conventional techniques of fibrinogen purification. Indeed, fibrinogen Marburg I with the A alpha chains depleted of the carboxy-terminal A alpha(461-610) residue segment has been purified by this technique, although this dysfibrinogen was difficult to purify by conventional precipitation techniques.

Antibodies, Monoclonal↗

Direct evidence for systemic fibrinogenolysis in patients with acquired alpha 2-plasmin inhibitor deficiency.

To examine whether or not acquired alpha 2-plasmin inhibitor deficiency is associated with systemic fibrinogenolysis, we analyzed the fibrin and fibrinogen degradation products in eight patients with this condition in various disease states. The underlying disease was gastric cancer in three patients, metastatic prostatic cancer in two, acute promyelocytic leukemia in two, and abdominal aortic aneurysm in one patient. In all eight patients, the alpha 2-plasmin inhibitor level was reduced to less than 50% of normal, and plasmin-alpha 2-plasmin inhibitor complex levels were increased. Immunoblotting of serum using an antifibrinogen antibody detected a 250 kDa protein (corresponding to fragments X or DY) in all eight patients. Fragment Y and D monomer were detected in seven of the eight patients, indicating the occurrence of systemic fibrinogenolysis. However, they were not detected in one patient with metastatic prostatic cancer. To determine whether or not fibrinogen degradation was also occurring in the patient without fragment Y, we characterized the 250 kDa protein in all eight patients. The protein was found to be fragment X in the metastatic prostatic cancer patient without fragment Y, while it was fragment DY in the other seven patients. Thus, systemic fibrinogenolysis was present in all eight patients. In the two patients with metastatic prostatic cancer, the level of alpha 2-plasmin inhibitor gradually increased with the reduction of tumor size by treatment. Fragment X, fragment Y, and D monomer were not detected when the alpha 2-plasmin inhibitor level exceeded 60% of normal in both patients. In the other six patients fragment Y and D monomer also disappeared when the alpha 2-plasmin inhibitor level exceeded 60% of normal. These findings suggest that systemic fibrinogenolysis only occurs when the plasma levels of alpha 2-plasmin inhibitor falls below 60% of normal due to activation of the fibrinolytic system by various pathological conditions.

Adult↗

Assessment of membrane fusion efficiency and its use for distinguishing epitopes on the fusion (F) protein of Sendai virus (HVJ).

Upon incubation of radioiodinated Sendai virus with Ehrlich ascites tumor cells to induce viral envelope-cell membrane fusion, TCA-soluble radioactivity was found to be rapidly released from the virus into the medium. The amount of the TCA-soluble 125I species released into the medium was correlated with the extent of envelope-membrane fusion. Using a new method based on this phenomenon, we evaluated the fusion-inhibiting activity of monoclonal anti-F protein antibodies and could distinguish epitopes within partially overlapping regions of the F protein by their effects on fusion activity. We concluded this method is a reliable and sensitive one for measuring envelope-membrane fusion.

Animals↗

Immunologic significance of diverse specificity of monoclonal antibodies against mannans of Candida albicans.

Two agglutinating IgM mAb against mannan Ag of Candida albicans strains were investigated for their specificity. The agglutinating patterns of both mAb with a panel of stationary phase of yeast cells of standard strains did not match those of any known polyclonal antibody (PAb) factors. The reactive patterns of both mAb for a given panel of 202 isolates of seven Candida species and the mode of competitive binding between mAb and a PAb factor, as determined by a combination of direct and indirect immunofluorescence staining, demonstrated that the two mAb were a part of PAb factor 4 (a prescribed reactive pattern of adsorbed PAb) but were different from each other in their specificity. The thereby designated mAb 4b and 4c were tested under PAb factor 4-positive Candida strains and further division into two to three serotypes of each species were made. 1H-Nuclear magnetic resonance spectra (500 MHz) of purified neutral mannans from strains of each serotype showed that although the 1H-nuclear magnetic resonance spectra of mannans from two subtypes of C. albicans serotype A and from each of two serotypes of Candida guilliermondii and Candida glabrata were identical or similar, the two mAb were still able to distinguish their fine determinant structures. Our findings suggest that mAb with entirely identical specificity cannot be produced against even the same determinant groups of mannan. In addition, the fact that microheterogeneity may occur without limit in the mannans of the strains suggests that antibodies with unlimited diverse specificities are produced directed against these antigenic varieties as well.

Agglutination Tests↗

Characterization of alternate and truncated forms of murine c-myb proteins.

The expression of c-myb proteins in transformed and normal murine cells was investigated. Two c-myb proteins, p75c-myb and p90c-myb, were detected in normal thymocytes and cell lines with intact c-myb genes. These most likely differ by the inclusion of additional amino acids encoded by an alternatively spliced c-myb mRNA. The use of this alternative exon is therefore not a feature exclusively of those cells with viral integrations in their c-myb gene. Smaller c-myb proteins in myeloid leukemic cell lines with rearranged c-myb genes were also characterized. Viral integration into the 5' region of the c-myb gene in the W265 and W274 cell lines leads to the synthesis in each case of two amino-terminally truncated c-myb proteins. By contrast, in NFS60 cells, viral integration into a more 3' region of the c-myb locus (but upstream of an alternate exon) leads to the production of a single p50c-myb protein.

Animals↗

Preparation and characterization of monoclonal antibodies against the human thrombin-antithrombin III complex.

Monoclonal antibodies were raised against human thrombin-antithrombin III complex by a hybridoma technique. Among them, five monoclonal antibodies, designated as JITAT-4, -14, -16, -17 and -19, were found to react with thrombin-antithrombin III, but not with its nascent components, alpha-thrombin or antithrombin III. Their respective immunoglobulin classes are IgG1 for JITAT-16 and -19, and IgG2a for JITAT-4, -14 and -17. Besides the thrombin-antithrombin III complex, they all bound to the Factor Xa-antithrombin III complex and the active-site-cleaved two-chain antithrombin III as well. Moreover, the reactivity of these two antibodies to the neoantigens was not affected by heparin, suggesting that their epitopes are independent of heparin-induced conformational changes of antithrombin III. Two of them, JITAT-16 and -17, were categorized as high-affinity antibodies to thrombin-antithrombin III complex, the dissociation constants being 6.7 nM and 4.8 nM, respectively. However, they do not share antigenic determinants. These monoclonal antibodies may allow us to explore more precisely the reaction between antithrombin III and thrombin or its related enzymes.

Antibodies, Monoclonal↗

Production and characterization of agglutinating monoclonal antibodies against predominant antigenic factors for Candida albicans.

Two clones, CA4-2 and CA5-4, which produced agglutinating monoclonal immunoglobulin M (IgM) antibodies (MAbs) against mannan antigens of Candida albicans serotype A, were established. The specificity of each MAb was determined by slide agglutination tests for cross-reactivity patterns against the homologous and six other strains of Candida and a strain of Torulopsis: C. albicans serotype B, C. tropicalis, C. guilliermondii, C. krusei, C. parapsilosis, C. pseudotropicalis, and Torulopsis glabrata. The MAb produced by CA4-2 reacted with the homologous, C. tropicalis, and T. glabrata strains, whereas the MAb produced by CA5-4 reacted with the homologous, C. albicans serotype B, and C. tropicalis strains. These results are consistent with results obtained by comparative experiments with several strains of each serotype or species. Specificity of these two MAbs by agglutination was also consistent with the cross-reactivity patterns demonstrated by indirect immunofluorescence staining. The competitive binding experiments by immunofluorescence staining with two MAbs and polyclonal factor sera (PAb factors) 5 and 6 suggested that the MAb from clone CA4-2 did not completely correspond to PAb factor 6 and that the MAb from CA5-4 was distinct from PAb factor 5 in its manner of binding to determinants (the latter was designated 5b), Cross-reactivity patterns, however, furnished evidence that these two MAbs could replace the known PAb factors 6 and 5, respectively, as reagents for aid in the identification of the strains of C. albicans and their serotypes.

Agglutination↗

A new homogeneous enzyme immunoassay. Its application to measurement of alpha-fetoprotein.

A rapid and sensitive homogeneous enzyme immunoassay (homogeneous EIA) was developed for determination of serum proteins such as alpha-fetoprotein (AFP). There are two assay systems, one is a competitive system including horseradish peroxidase (HRP)-labeled antigen, antibody and substrate, and the other is a non-competitive system including HRP-labeled antibody and substrate. When the aggregate was formed through the binding of HRP-labeled AFP and anti-AFP antibody or through the binding of HRP-labeled anti-AFP antibody and AFP, HRP of the aggregates, as compared with HRP of free conjugates, exhibited marked activity in the presence of 35 mM H2O2. The extent of stimulation of HRP activity depended on the amount of AFP. This new assay method is very simple and sensitive, and can be used for the determination of any kind of protein, hormone, or drug.

Antibodies↗

Purification and properties of polynucleotide phosphorylase from photosynthetic bacterium Rhodospirillum rubrum.

1. Polynucleotide phosphorylase [polyribonucleotide: orthophosphate nucleotidyltransferase, EC 2.7.7.8] was purified to near homogeneity from the photosynthetic bacterium, Rhodospirillum rubrum. The purified enzyme had a molecular weight of approximately 160,000, and consisted of two equivalent subunits of approximately 76,000 daltons. It catalyzed the three reactions described below. 2. In the exchange reaction of the beta-phosphate of nucleoside diphosphates with Pi by the purified enzyme in the presence of 3.3 mM Pi, 6.7 mMCl2, and 0.33 mM or 1.0 mM nucleotide at pH 8.0 and 20 degrees C, ADP, GDP, and CDP, and CDP were better substrates than UDP, while IDP and deoxyribonucleoside diphosphates hardly served as substrates. The ADP-Pi exchange activity was significantly inhibited by high concentrations of either ADP or Pi. 3. In the polymerization reaction of ribonucleoside diphosphates by the purified enzyme in the presence of 6.7 mM nucleotide and 6.7 mM MgCl2 at pH 8.0 and 20 degrees C, ADP was the best substrate; the activities relative to that with ADP were 55% with UD, 51% with CDP, and 48% with IDP, while GDP hardly served as a substrate, 4. In the phosphoryolysis reaction of polynucleoside diphosphates by the purified enzyme in the presence of 1.0 mM polynucleotide, 6.7 mM Pi, and 6.7 mM MgCl2 at pH 8.0 and 20 degrees C, poly[U] was the best substrate; the activities relative to that with poly[U] were 32% with poly[A], 28% with poly[I], 21% with poly[C], and 2% with yeast RNA, while poly[G] and yeast DNA hardly served as substrates. 5. The three kinds of activities of the purified enzyme described above were stimulated by divalent cations such as Mg2+, Mn2+, Cd2+, and Co2+.

Cations, Divalent↗