scholarly journals Binding characteristics of antibodies to the TSH receptor

1998 ◽  
Vol 20 (2) ◽  
pp. 233-244 ◽  
Author(s):  
Y Oda ◽  
J Sanders ◽  
S Roberts ◽  
M Maruyama ◽  
R Kato ◽  
...  

We have used fragments of the TSH receptor (TSHR) expressed in E. coli as glutathione S-transferase fusion proteins to produce rabbit polyclonal antibodies and a panel (n=5) of monoclonal antibodies to the extracellular fragment of the TSHR. The binding characteristics of the antibodies to linear, conformational, glycosylated and unglycosylated forms of the receptor in different assay systems have been investigated. The reactivity of these antibodies with the TSHR was assessed by Western blotting with both native and recombinant human TSHR expressed in CHO cells, immunoprecipitation of 35S-labelled full-length TSHR produced in an in vitro transcription/ translation system, immunoprecipitation of 125I-TSH/TSHR complexes, inhibition of 125I-TSH binding to the TSHR and fluorescence activated cell sorter (FACS) analysis of binding to CHO-K1 cells expressing the TSHR on their cell surface. Fab fragments of monoclonal antibodies were isolated, labelled with 125I and used to determine the affinity constants of these antibodies with receptor, bound and free Fab being separated by polyethylene glycol (PEG) precipitation. Rabbit polyclonal and mouse monoclonal antibodies reacted with the TSHR in Western blotting and one monoclonal antibody (3C7) was able to inhibit 125I-TSH binding to native human TSHR (74% inhibition), recombinant human TSHR (84% inhibition) and porcine TSHR (65% inhibition). Affinity constant values for TSHR monoclonal antibody Fab fragments calculated using Scatchard analysis were about 10(7) M(-1). Four out of five monoclonal antibodies reacted in FACS analysis with TSHR expressed on the surface of CHO-K1 cells. The FACS unreactive monoclonal (3C7) bound well to detergent solubilised TSH receptors and this emphasised the importance of using a combination of FACS analysis and radioactively-labelled probes in analysis of the TSH receptor. The monoclonal antibodies produced in this study were found to be of relatively low affinity but proved useful for detection of the receptor by Western blotting and by FACS analysis.

2021 ◽  
Vol 22 (6) ◽  
pp. 3166
Author(s):  
Jwala Priyadarsini Sivaccumar ◽  
Antonio Leonardi ◽  
Emanuela Iaccarino ◽  
Giusy Corvino ◽  
Luca Sanguigno ◽  
...  

Background: Monoclonal antibodies (mAbs) against cancer biomarkers are key reagents in diagnosis and therapy. One such relevant biomarker is a preferentially expressed antigen in melanoma (PRAME) that is selectively expressed in many tumors. Knowing mAb’s epitope is of utmost importance for understanding the potential activity and therapeutic prospective of the reagents. Methods: We generated a mAb against PRAME immunizing mice with PRAME fragment 161–415; the affinity of the antibody for the protein was evaluated by ELISA and SPR, and its ability to detect the protein in cells was probed by cytofluorimetry and Western blotting experiments. The antibody epitope was identified immobilizing the mAb on bio-layer interferometry (BLI) sensor chip, capturing protein fragments obtained following trypsin digestion and performing mass spectrometry analyses. Results: A mAb against PRAME with an affinity of 35 pM was obtained and characterized. Its epitope on PRAME was localized on residues 202–212, taking advantage of the low volumes and lack of fluidics underlying the BLI settings. Conclusions: The new anti-PRAME mAb recognizes the folded protein on the surface of cell membranes suggesting that the antibody’s epitope is well exposed. BLI sensor chips can be used to identify antibody epitopes.


1982 ◽  
Vol 208 (3) ◽  
pp. 641-649 ◽  
Author(s):  
Toshihiro Yagura ◽  
Paul G. Walfish

Endogenous l-tri-iodothyronine content in an hepatic nuclear extract was measured by a new unextracted-sample radioimmunoassay method using 8-anilinonaphthalene-1-sulphonic acid to inhibit the l-[125I]tri-iodothyronine binding to the nuclear l-tri-iodothyronine receptor within the extract. For this method, the lower sensitivity limit was 3.125 pg/tube, the recovery of added l-tri-iodothyronine was 90–120%, and the between-assay coefficient of variation was 10%. The amount of endogenous l-tri-iodothyronine was 10–40 pg/0.2 ml of hepatic nuclear extract from euthyroid rats, compared with less than 3.125 pg/0.2 ml from thyroidectomized rats. The results obtained by this new method were compared with a Sephadex G-25 column extracted-sample radioimmunoassay method and showed a good agreement. The values for the endogenous l-tri-iodothyronine content were utilized to correct for the l-tri-iodothyronine concentration within the binding assay mixture in order to accurately determine by Scatchard analysis the binding characteristics of the nuclear l-tri-iodothyronine receptor. The validity of the correction for endogeneous l-tri-iodothyronine was demonstrated by using a nuclear extract from a thyroidectomized rat which was preincubated with a small known amount of l-tri-iodothyronine before determining the nuclear l-tri-iodothyronine receptor binding characteristics. When the Scatchard plots were corrected for the preincubated dose, the results obtained were similar to true values, but they were falsely lower when not corrected. It is concluded that the necessity and validity of using endogenous l-tri-iodothyronine corrections in the Scatchard analytical computations of the nuclear l-tri-iodothyronine receptor binding characteristics has been demonstrated, being particularly more important for affinity constant than maximum binding capacity.


2019 ◽  
Vol 6 (3) ◽  
pp. e547 ◽  
Author(s):  
Maartje G. Huijbers ◽  
Dana L. Vergoossen ◽  
Yvonne E. Fillié-Grijpma ◽  
Inge E. van Es ◽  
Marvyn T. Koning ◽  
...  

ObjectiveTo isolate and characterize muscle-specific kinase (MuSK) monoclonal antibodies from patients with MuSK myasthenia gravis (MG) on a genetic and functional level.MethodsWe generated recombinant MuSK antibodies from patient-derived clonal MuSK-specific B cells and produced monovalent Fab fragments from them. Both the antibodies and Fab fragments were tested for their effects on neural agrin-induced MuSK phosphorylation and acetylcholine receptor (AChR) clustering in myotube cultures.ResultsThe isolated MuSK monoclonal antibody sequences included IgG1, IgG3, and IgG4 that had undergone high levels of affinity maturation, consistent with antigenic selection. We confirmed their specificity for the MuSK Ig-like 1 domain and binding to neuromuscular junctions. Monovalent MuSK Fab, mimicking functionally monovalent MuSK MG patient Fab-arm exchanged serum IgG4, abolished agrin-induced MuSK phosphorylation and AChR clustering. Surprisingly, bivalent monospecific MuSK antibodies instead activated MuSK phosphorylation and partially induced AChR clustering, independent of agrin.ConclusionsPatient-derived MuSK antibodies can act either as MuSK agonist or MuSK antagonist, depending on the number of MuSK binding sites. Functional monovalency, induced by Fab-arm exchange in patient serum, makes MuSK IgG4 antibodies pathogenic.


1987 ◽  
Vol 116 (1_Suppl) ◽  
pp. S173-S180 ◽  
Author(s):  
N.J. Marshall ◽  
L. D. Kohn ◽  
P. A. Ealey

Abstract. The monoclonal antibody 11E8 (Kohn et al. 1984) is a novel proof of the actions of thyroid stimulator, since it is not only a potent stimulator of thyroid cells but also an inhibitor for TSH-binding. This might reflect an interaction of 11E8 with a discrete domaine of the TSH receptor, which is an essential component for TSH but not for TSab actions. These unique properties of 11E8 can be applied to the characterization of other thyroid stimulators which may interact with different domaines of the receptor. Moreover, 'TSab-like' stimulators, such as the sheep anti-TSH antiserum, could potentially be identified by 11E8.


1988 ◽  
Vol 118 (1) ◽  
pp. 69-80 ◽  
Author(s):  
S. T. Ellis ◽  
R. B. Heap ◽  
A. R. Butchart ◽  
V. Rider ◽  
N. E. Richardson ◽  
...  

ABSTRACT Anti-progesterone monoclonal antibody prevents the establishment of pregnancy in BALB/c mice by the prevention of implantation when injected i.p. 32 h after mating. To determine the specificity of this effect, mice were injected with immune and non-immune purified mouse immunoglobulins. The results show that anti-implantation efficacy was due to high-affinity antibody which bound progesterone since two further mouse immunoglobulin (Ig) G1 preparations, mouse IgA and mouse IgM which failed to bind the steroid, had no effect on pregnancy rates. From a panel of anti-progesterone monoclonal antibodies, six with a high affinity (affinity constant, 0·24–0·80 litres/nmol) and specificity for progesterone were selected for additional studies. Anti-implantation efficacy for five antibodies was similar, with a 50% effective dose within the range of 0·8–2·0 nmol. Antibody reached high concentrations in plasma within 12 h after i.p. injection, and declined with a half-life of about 80 h. Purified F(ab′)2 fragments of antibody also bound progesterone, but were less effective than the native molecule in blocking pregnancy. The results show that implantation in the mouse can be blocked by a high-affinity antibody that binds progesterone and which is removed from the blood at a slow rate. J. Endocr. (1988) 118, 69–80


Blood ◽  
1988 ◽  
Vol 72 (5) ◽  
pp. 1740-1747 ◽  
Author(s):  
H Takami ◽  
WL Nichols ◽  
SE Kaese ◽  
RS Miller ◽  
JA Katzmann ◽  
...  

Abstract We prepared murine monoclonal antibodies to porcine platelet membrane glycoprotein (GP) Ib and GP IIb/IIIa for further study of the porcine hemostatic mechanism. One monoclonal antibody, designated PP3–4C, blocked Ristocetin-induced platelet agglutination and caused 80% inhibition of Ristocetin-induced 125I-von Willebrand factor (vWF) binding to porcine platelets at a concentration of greater than or equal to 12 micrograms IgG/mL. PP3–4C did not affect adenosine diphosphate (ADP)- or collagen-induced platelet aggregation. Binding of 125I-Fab fragments of PP3–4C to platelets was saturable at 3.7 x 10(4) +/- 0.8 x 10(4) molecules per platelet. Another monoclonal antibody, designated PP3–3A, blocked ADP- or collagen-induced platelet aggregation at 6 micrograms IgG/mL. At a concentration of 10 micrograms IgG/mL, PP3–3A completely inhibited binding either of 125I-fibrinogen or of 125I-vWF to ADP-stimulated platelets. PP3–3A did not affect Ristocetin-induced platelet agglutination nor 125I-vWF binding to platelets in the presence of Ristocetin. Binding of 125I-Fab' fragments of PP3–3A to platelets was saturable at 9.8 x 10(4) +/- 1.2 x 10(4) molecules per platelet. PP3–4C antibody (anti-GP Ib) did not bind to human platelets; however, PP3–3A antibody (anti-GP IIb-IIIa) had partial cross-reactivity with human platelets. Immunoaffinity chromatography of solubilized surface-radiolabeled porcine platelets and subsequent sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis demonstrated that PP3–4C recognized a GP with an apparent molecular weight of 160,000 (nonreduced), and 140,000 (reduced). PP3–3A recognized GPs with apparent molecular weights of 130,000 and 80,000 (nonreduced), and 115,000 and 95,000 (reduced). These monoclonal antibodies to porcine platelet membrane GPs, which are structural and functional analogues of human GP Ib and GP IIb/IIIa, will be useful for in vitro and in vivo studies of the mammalian hemostatic mechanism.


1987 ◽  
Author(s):  
H Takami ◽  
W L Nichols ◽  
S E Kaese ◽  
R S Miller ◽  
J A Katzmann ◽  
...  

For further study of the porcine hemostatic mechanism, we have prepared murine monoclonal antibodies, and F(ab')2 and Fab fragments, specific for porcine platelet membrane glycoproteins GP lb and GP Ilb/IIIa. To avoid production of antibodies to von Willebrand factor (vWF), mice were immunized with platelets obtained from pigs with severe von Willebrand,s disease. One monoclonal antibody (PP3-4C), of IgG1 subclass, caused 85% inhibition of Ristocetin-induced platelet binding of 125I-vWF (porcine) at ≥12 µg IgG/ml. PP3-4C did not affect ADP or collagen-induced platelet aggregation nor inhibit 125I-fibrinogen (porcine) binding. Pepsin and papain digestion, respectively, were used to prepare PP3-4C F(ab')2 and Fab fragments. PP3-4C F(ab')2 at concentrations ≥12 µg/ml caused 80% inhibition of washed platelet agglutination in the presence of vWF and Ristocetin, whereas Fab fragments at concentrations ≥10 µg/ml caused 60% inhibition. Another monoclonal antibody (PP3-3A), of IgG1 subclass, completely inhibited ADP or collagen-induced platelet aggregation at an IgG concentration of 6 µg/ml. At 10 µg IgG/ml PP3-3A completely inhibited binding either of 125I-fibrinogen or of 125I-vWF to ADP-stimulated porcine platelets. PP3-3A did not affect vWF-dependent Ristocetin-induced platelet agglutination, nor 125I-vWF binding to platelets in the presence of Ristocetin. PP3-3A did not bind to platelets which were treated with 10 mM EDTA at 37°C for 60 min. F(ab')2 and Fab fragments were isolated from PP3-3A pepsin or papain digests. Both types of PP3-3A fragments caused 100% inhibition of ADP-induced platelet aggregation, at concentrations ≥6 yg/ml. Immunoprecipitation of surface-radiolabeled porcine platelets and subsequent SDS-PAGE demonstrated that PP3-4C recognized a glycoprotein with molecular weight of 140,000 (under reducing conditions), and 165,000 (non-reduced). PP3-3A recognized glycoproteins with molecular weights of 115,000 and 100,000 (reduced), and 130,000 and 80,000 (non-reduced). Neither monoclonal antibody bound to human platelets. These monoclonal antibodies to porcine platelet membrane glycoproteins which are analogues of human GP lb and GP Ilb/IIIa will be useful for in vitro and in vivo studies to further understanding of mammalian hemostatic mechanisms.


Blood ◽  
1988 ◽  
Vol 72 (5) ◽  
pp. 1740-1747
Author(s):  
H Takami ◽  
WL Nichols ◽  
SE Kaese ◽  
RS Miller ◽  
JA Katzmann ◽  
...  

We prepared murine monoclonal antibodies to porcine platelet membrane glycoprotein (GP) Ib and GP IIb/IIIa for further study of the porcine hemostatic mechanism. One monoclonal antibody, designated PP3–4C, blocked Ristocetin-induced platelet agglutination and caused 80% inhibition of Ristocetin-induced 125I-von Willebrand factor (vWF) binding to porcine platelets at a concentration of greater than or equal to 12 micrograms IgG/mL. PP3–4C did not affect adenosine diphosphate (ADP)- or collagen-induced platelet aggregation. Binding of 125I-Fab fragments of PP3–4C to platelets was saturable at 3.7 x 10(4) +/- 0.8 x 10(4) molecules per platelet. Another monoclonal antibody, designated PP3–3A, blocked ADP- or collagen-induced platelet aggregation at 6 micrograms IgG/mL. At a concentration of 10 micrograms IgG/mL, PP3–3A completely inhibited binding either of 125I-fibrinogen or of 125I-vWF to ADP-stimulated platelets. PP3–3A did not affect Ristocetin-induced platelet agglutination nor 125I-vWF binding to platelets in the presence of Ristocetin. Binding of 125I-Fab' fragments of PP3–3A to platelets was saturable at 9.8 x 10(4) +/- 1.2 x 10(4) molecules per platelet. PP3–4C antibody (anti-GP Ib) did not bind to human platelets; however, PP3–3A antibody (anti-GP IIb-IIIa) had partial cross-reactivity with human platelets. Immunoaffinity chromatography of solubilized surface-radiolabeled porcine platelets and subsequent sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis demonstrated that PP3–4C recognized a GP with an apparent molecular weight of 160,000 (nonreduced), and 140,000 (reduced). PP3–3A recognized GPs with apparent molecular weights of 130,000 and 80,000 (nonreduced), and 115,000 and 95,000 (reduced). These monoclonal antibodies to porcine platelet membrane GPs, which are structural and functional analogues of human GP Ib and GP IIb/IIIa, will be useful for in vitro and in vivo studies of the mammalian hemostatic mechanism.


2000 ◽  
Vol 74 (17) ◽  
pp. 7922-7935 ◽  
Author(s):  
Aimee L. Edinger ◽  
Ména Ahuja ◽  
Tina Sung ◽  
Kelly C. Baxter ◽  
Beth Haggarty ◽  
...  

ABSTRACT In an attempt to generate broadly cross-reactive, neutralizing monoclonal antibodies (MAbs) to simian immunodeficiency virus (SIV), we compared two immunization protocols using different preparations of oligomeric SIV envelope (Env) glycoproteins. In the first protocol, mice were immunized with soluble gp140 (sgp140) from CP-MAC, a laboratory-adapted variant of SIVmacBK28. Hybridomas were screened by enzyme-linked immunosorbent assay, and a panel of 65 MAbs that recognized epitopes throughout the Env protein was generated. In general, these MAbs detected Env by Western blotting, were at least weakly positive in fluorescence-activated cell sorting (FACS) analysis of Env-expressing cells, and preferentially recognized monomeric Env protein. A subset of these antibodies directed toward the V1/V2 loop, the V3 loop, or nonlinear epitopes were capable of neutralizing CP-MAC, a closely related isolate (SIVmac1A11), and/or two more divergent strains (SIVsmΔB670 CL3 and SIVsm543-3E). In the second protocol, mice were immunized with unfixed CP-MAC-infected cells and MAbs were screened for the ability to inhibit cell-cell fusion. In contrast to MAbs generated against sgp140, the seven MAbs produced using this protocol did not react with Env by Western blotting and were strongly positive by FACS analysis, and several reacted preferentially with oligomeric Env. All seven MAbs potently neutralized SIVmac1A11, and several neutralized SIVsmΔB670 CL3 and/or SIVsm543-3E. MAbs that inhibited gp120 binding to CD4, CCR5, or both were identified in both groups. MAbs to the V3 loop and one MAb reactive with the V1/V2 loop interfered with CCR5 binding, indicating that these regions of Env play similar roles for SIV and human immunodeficiency virus. Remarkably, several of the MAbs generated against infected cells blocked CCR5 binding in a V3-independent manner, suggesting that they may recognize a region analogous to the conserved coreceptor binding site in gp120. Finally, all neutralizing MAbs blocked infection through the alternate coreceptor STRL33 much more efficiently than infection through CCR5, a finding that has important implications for SIV neutralization assays using CCR5-negative human T-cell lines.


2000 ◽  
Vol 11 (12) ◽  
pp. 4369-4380 ◽  
Author(s):  
Nathalie Avazeri ◽  
Anne-Marie Courtot ◽  
Arlette Pesty ◽  
Clotilde Duquenne ◽  
Brigitte Lefèvre

The location of the phospholipase C β1-isoform (PLC-β1) in the mouse oocyte and its role in the resumption of meiosis were examined. We used specific monoclonal antibodies to monitor the in vitro dynamics of the subcellular distribution of the enzyme from the release of the oocyte from the follicle until breakdown of the germinal vesicle (GVBD) by Western blotting, electron microscope immunohistochemistry, and confocal microscope immunofluorescence. PLC-β1 became relocated to the oocyte cortex and the nucleoplasm during the G2/M transition, mainly in the hour preceding GVBD. The enzyme was a 150-kDa protein, corresponding to PLC-β1a. Its synthesis in the cytoplasm increased during this period, and it accumulated in the nucleoplasm. GVBD was dramatically inhibited by the microinjection of anti-PLC-β1 monoclonal antibody into the germinal vesicle (GV) only when this accumulation was at its maximum. In contrast, PLC-γ1 was absent from the GV from the time of release from the follicle until 1 h later, and microinjection of anti-PLC-γ1 into the GV did not affect GVBD. Our results demonstrate a relationship between the relocation of PLC-β1 and its role in the first step of meiosis.


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