Epitope Mapping of Inhibitory Monoclonal Antibodies to Human von Willebrand Factor by Using Recombinant cDNA Libraries

1994 ◽  
Vol 71 (06) ◽  
pp. 788-792 ◽  
Author(s):  
Geneviéve Piétu ◽  
Anne-Sophie Ribba ◽  
Ghislaine Chérel ◽  
Virginie Siguret ◽  
Bernadette Obert ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
Recombinant Expression ◽  
Cdna Libraries ◽  
Integrin Receptors ◽  
Binding Domains ◽  
Rgd Sequence ◽  
Adhesive Proteins ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryTwo recombinant expression libraries containing small (300-600 base pairs) cDNA fragments of von Willebrand Factor (vWF) were screened in order to map the epitope of monoclonal antibodies (MAbs) to vWF. Among eleven MAbs tested, seven were effectively mapped. The epitopes of MAbs 418 and 522, which inhibit the binding of vWF to Factor VIII (FVIII), were localized between Leu 2 and Arg 53 and between Glu 35 and He 81 of the vWF subunit respectively, within the N-terminal trypsin fragment called SpIII-T4 [amino acids (aa) 1-272] which contains a binding domain for FVIII. The epitope of MAb 710, which inhibits the binding of vWF to glycoprotein lb (GPIb), was identified between Ser 593 and Ser 678 on the tryptic 52/48 kDa fragment (aa 449-728) which contains binding domains for GPIb, collagen, heparin, sulfatides and subendothclium extracellular matrices. The epitope of MAb 723, which does not interfere with any known function of vWF, was localized between Ser 523 and Gly 588. The epitopes of MAb 505 and MAb 400, which inhibit the binding of v WF to collagen, were identified between Leu 927 and Arg 1114 within the SPI fragment (aa 911-1365) corresponding to the central part of the vWF subunit. The epitope of MAb 9, which inhibits the binding of vWF to GPIIb/IIIa, was identified in the C-terminal part of the vWF subunit between Gin 1704 and Asp 1746, the latter being the third aa of the RGD sequence common to adhesive proteins and serving as a recognition site for integrin receptors.

scholarly journals Epitope mapping by cDNA expression of a monoclonal antibody which inhibits the binding of von Willebrand factor to platelet glycoprotein IIb/IIIa

1992 ◽  
Vol 284 (3) ◽  
pp. 711-715 ◽  
Author(s):  
G Piétu ◽  
A S Ribba ◽  
G Chérel ◽  
D Meyer
Keyword(s):  
Monoclonal Antibody ◽  
Von Willebrand Factor ◽  
Fusion Proteins ◽  
Solid Phase ◽  
Platelet Glycoprotein ◽  
Rgd Sequence ◽  
Adhesive Proteins ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Beta Galactosidase

In order to study the structure-function relationship of von Willebrand Factor (vWF), we have located the epitope of a well-characterized monoclonal antibody (MAb) to vWF (MAb 9). This MAb reacts with the C-terminal portion of the vWF subunit, SPII fragment [amino acids (aa) 1366-2050], which includes an Arg-Gly-Asp (RGD) sequence at positions 1744-1746, and totally inhibits vWF and SPII binding to platelet membrane glycoprotein IIb/IIIa (GPIIb/IIIa). A recombinant DNA library was constructed by cloning small (250-500 nucleotides) vWF cDNA fragments into the lambda gt11 vector and these inserts were expressed as fusion proteins with beta-galactosidase. Immunological screening of the library with 125I-MAb 9 identified three immunoreactive clones. vWF inserts were amplified by the PCR and their sequences demonstrated overlapping nucleotides from positions 7630 to 7855 of vWF cDNA, coding for aa residues 1698-1773 of the mature subunit, indicating that this is the epitope of MAb 9. vWF-beta-galactosidase fusion protein reacted with 125I-MAb 9 by Western blotting. In a solid-phase radioimmunoassay, the purified fusion proteins decreased the binding of vWF to 125I-MAb 9 by 50%, and this inhibition was dose-dependent between 3.5 and 120 nM. Therefore the epitope of MAb 9 is located within aa 1698-1773 of the vWF subunit, which includes the RGD sequence implicated in the binding of adhesive proteins of GPIIb/IIIa.

SYNTHETIC RGD-CONTAINING PEPTIDES OF VON WILLEBRAND FACTOR INHIBIT PLATELET ADHESION TO COLLAGEN

1987 ◽  
Author(s):  
E Fresslnaud ◽  
J E Sadler ◽  
J P Girma ◽  
H R Baumgartner ◽  
D Meyer
Keyword(s):  
Platelet Aggregation ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Dependent Manner ◽  
Rgd Peptides ◽  
Rgd Sequence ◽  
Adhesive Proteins ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Dose Dependent

The Arg-Gly-Asp (RGD) sequence is common to fibrinogen (Fg), fibronectin (Fn) and von Willebrand Factor (vWF). RGD-containing peptides compete for binding of these adhesive proteins to platelet membrane GPIIb/IIIa and inhibit thrombin-induced platelet aggregation as does an unrelated dodecapeptide from the γ Fg COOH terminus (γFg 400-411). We compared in flowing blood the effect of γ Fg 400-411 and of 3 synthetic peptides derived from the sequence of human vWF upon platelet adhesion to collagen. The 3 vWF peptides (13 or 18 aminoacids) contained an RGD sequence in the NH2 (peptide 03), central (peptide 07) or COOH (peptide 02) portions. Collagen was coated onto plastic coverslips and exposed in a parallel-plate perfusion chamber to reconstituted human blood at a shear rate of 2,600 s™1 for 3 min at 37°C. Perfusates contained physiological concentrations of 51 Cr-platelets and red cells in either citrated autologous plasma or modified Tyrode buffer containing 4% human albumin ; in the latter case, the collagen-coated coverslips were preincubated with normal plasma or purified human vWF prior to perfusion. Platelet-collagen interactions were estimated by radioactivity counting and quantitative morphometry. RGD peptides 02, 03 and 07 inhibited platelet-collagen interactions in a dose-dependent manner. With peptide 07, deposition of 51 Cr-platelets decreased from 283.8 ± 32.5 × 105/cm2 (mean ± SEM, n = 3) with buffer to 169.6 ± 33.0 in the presence of 50 μM peptide (p < 0.05), 133.7 ± 26.4 with 150 uM (p <0.012) and 101.8 ± 27.1 with 300 uM (p <0.005). The inhibitory effect of γ Fg 400-411 upon platelet deposition was less significant than that of the RGD peptides at 50 and 150 uM concentrations (224.4 ± 39.8, N.S. and 139.5 ± 55.3, p < 0.05, respectively). RGD peptide 07 also inhibited in a dose-dependent way both platelet adhesion to collagen and thrombus growth. Similar results were observed with peptides 02 and 03, indicating that the position of the RGD sequence is not critical. No synergetic effect between RGD and γFg 400-411 peptides was observed. These results with vWF peptides confirm that GPIIb/IIIa is involved not only In platelet aggregation (thrombus growth) but also in vWF-mediated platelet adhesion to collagen.

The Interaction of Botrocetin with Normal or Variant von Willebrand Factor (Types IIA and IIB) and Its Inhibition by Monoclonal Antibodies that Block Receptor Binding

1992 ◽  
Vol 68 (04) ◽  
pp. 464-469 ◽  
Author(s):  
Y Fujimura ◽  
S Miyata ◽  
S Nishida ◽  
S Miura ◽  
M Kaneda ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
Binding Activity ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Normal Individuals ◽  
Rag 1 ◽  
The One ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryWe have recently shown the existence of two distinct forms of botrocetin (one-chain and two-chain), and demonstrated that the two-chain species is approximately 30 times more active than the one-chain in promoting von Willebrand factor (vWF) binding to platelet glycoprotein (GP) Ib. The N-terminal sequence of two-chain botrocetin is highly homologous to sea-urchin Echinoidin and other Ca2+-dependent lectins (Fujimura et al., Biochemistry 1991; 30: 1957–64).Present data indicate that purified two-chain botrocetin binds to vWF from plasmas of patients with type IIA or IIB von Willebrand disease and its interaction is indistinguishable from that with vWF from normal individuals. However, an “activated complex” formed between botrocetin and IIB vWF expresses an enhanced biological activity for binding to GP Ib whereas the complex with IIA vWF has a decreased binding activity. Among several anti-vWF monoclonal antibodies (MoAbs) which inhibit ristocetin-induced platelet aggregation and/or vWF binding to GPIb, only two MoAbs (NMC-4 and RFF-VIII RAG:1) abolished direct binding between purified botrocetin and vWF. This suggests that they recognize an epitope(s) on the vWF molecule in close proximity to the botrocetin binding site.

scholarly journals Fibrinogen competes with von Willebrand factor for binding to the glycoprotein IIb/IIIa complex when platelets are stimulated with thrombin

Blood ◽  
1984 ◽  
Vol 64 (4) ◽  
pp. 797-800 ◽  
Author(s):  
HR Gralnick ◽  
SB Williams ◽  
BS Coller
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
Adenosine Diphosphate ◽  
Glycoprotein Ib ◽  
Human Fibrinogen ◽  
Factor Binding ◽  
Normal Plasma ◽  
Platelet Binding ◽  
Von Willebrand ◽  
Willebrand Factor

Two monoclonal antibodies--one that blocks ristocetin-induced platelet binding of von Willebrand factor to glycoprotein Ib and one that blocks adenosine diphosphate-induced binding of fibrinogen to the glycoprotein IIb/IIIa complex--were used to assess the binding site(s) for von Willebrand factor when platelets are stimulated with thrombin or adenosine diphosphate (ADP). Neither agonist induced binding of von Willebrand factor to glycoprotein Ib. ADP and thrombin induced von Willebrand factor binding exclusively to the glycoprotein IIb/IIIa complex. The results of the site of binding of von Willebrand factor with thrombasthenic platelets were consistent with the data obtained with the monoclonal antibodies and normal platelets. Human fibrinogen caused complete inhibition of thrombin-induced von Willebrand factor binding to normal platelets at concentrations considerably below that found in normal plasma. We conclude that thrombin induces very little binding of exogenous von Willebrand factor to platelets at normal plasma fibrinogen levels.

Isolation and characterization of collagen-binding domains from human von Willebrand factor

2009 ◽  
Vol 24 (3) ◽  
pp. 150-154 ◽  
Author(s):  
N. E. Sharapova ◽  
A. P. Kotnova ◽  
Z. M. Galushkina ◽  
N. N. Poletaeva ◽  
N. V. Lavrova ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Collagen Binding ◽  
Binding Domains ◽  
Isolation And Characterization ◽  
Von Willebrand ◽  
Willebrand Factor

scholarly journals The von willebrand factor domain-mediating botrocetin-induced binding to glycoprotein IB lies between Val449 and Lys728

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 985-988 ◽  
Author(s):  
Y Fujimura ◽  
LZ Holland ◽  
ZM Ruggeri ◽  
TS Zimmerman
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Von Willebrand Factor ◽  
Amino Acid Residue ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Tryptic Fragment ◽  
Alternative Agent ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Botrocetin, a component of Bothrops jararaca venom, induces von Willebrand factor (vWF)-dependent platelet agglutination and has been proposed as an alternative agent to ristocetin for evaluating vWF function. However, important differences between the vWF-platelet interactions induced by these two agents have suggested that different regions of vWF and the platelet may be involved in the interactions induced by the two agonists. We have recently demonstrated that binding of vWF to the platelet glycoprotein (GP) Ib receptor, either induced by ristocetin or as occurs spontaneously with asialo-vWF or vWF from IIb von Willebrand disease, is mediated by a domain residing on a 52/48- kilodalton (kD) tryptic fragment of vWF. This fragment extends from amino acid residue Val (449) to Lys (728). We have now found that this 52/48-kD fragment blocks botrocetin-induced binding of vWF to platelets and completely inhibits botrocetin-induced platelet agglutination. These results provide evidence that the vWF domain-mediating, botrocetin-induced platelet agglutination lies within the region delimited by this fragment and is therefore close to or identical with that which mediates ristocetin-induced binding and spontaneous binding of vWF to platelet GPIb. Anti-GPIb monoclonal antibodies also blocked agglutination, which showed that botrocetin, like ristocetin, induces binding of vWF to the GPIb receptor.

VON WILLEBRAND FACTOR (VWF) ANTIGENS IN URINE

1987 ◽  
Author(s):  
A M V Silveira ◽  
B Hessel ◽  
B Blombäck
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
High Performance ◽  
Molecular Size ◽  
Von Willebrand Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Normal Urine ◽  
Von Willebrand ◽  
Willebrand Factor

Human urine was analyzed using a sensitive enzyme linked immunosorbent assay (ELISA) for von Willebrand factor (VWF) antigen. Urine of healthy persons contained VWF immunoreactivity. In the urine of a patient with severe von Willebrand disease, the VWF antigen was only detectable after intravenous infusion of VWF-Factor VIII concentrate. The VWF antigen in normal urine was analyzed by gel permeation high performance liquid chromatography (HPLC) and gel electrophoresis combined with immunoblotting. These analyses revealed three immunoreactive components of Mr 350 kDa, 60 kDa, and 20 kDa, respectively, the 60 kDa being the major component. Monoclonal antibodies of known specificity to VWF molecule were used in ELISA and immunoblotting to analyze urinary VWF. The three components reacted with an antibody to the central part of VWF, which is called fragment I, and contains the binding site for collagen. No significant immunoreac-tion was observed with monoclonal antibodies to the Nor C-terminal portions of VWF.VWF derivatives of molecular size similar to the largest urinary antigens were also observed in normal plasma. However, there is not an obvious relationship between these plasma forms and the products in urine since reduction of plasma and urine yields different products.These results indicate that VWF antigens excreted in normal urine are most likely fragments of VWF produced by limited degradation in vivo. This degradation preserves the central part of VWF molecule, the one which reacts with the antibody that blocks the binding of VWF to collagen.

scholarly journals Effect of monoclonal antibodies against von Willebrand factor and platelet glycoproteins IIb/IIIa on the platelet retention test

Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 546-550 ◽  
Author(s):  
J McPherson ◽  
S Brownlea ◽  
MB Zucker
Keyword(s):  
Monoclonal Antibodies ◽  
Platelet Aggregation ◽  
Von Willebrand Factor ◽  
Retention Test ◽  
Platelet Adhesion ◽  
Glass Beads ◽  
Two Stage ◽  
Second Stage ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The platelet retention test provides a measure of the number of platelets retained in a column of glass beads and is one of the few in vitro platelet function tests that is abnormal in von Willebrand's disease (vWd). In a two-stage test, 1 mL of blood (designated A) was passed through the column, followed by 5 mL of isotonic saline and then 5 mL of blood (B) in which platelet retention was measured. With normal blood as A and B, retention is very high in all 5 mL of blood B. In the first stage, platelets adhere to the glass beads; this requires fibrinogen but not von Willebrand factor (vWf). The platelet-platelet adhesion in the second stage requires vWf, is dependent on release of ADP, and fails to occur if thrombasthenic platelets are tested. Retention was normal when blood from a patient with afibrinogenemia was used as blood B. We have now used monoclonal antibodies to elucidate further the mechanism of platelet retention. Five antibodies to different epitopes on vWf essentially abolished retention in the one- stage test and in the second stage of the two-stage test, but had no effect on the first stage. Thus, the entire vWf molecule must be free of antibody to function in the platelet-platelet adhesion of the second stage of this test. Binding of the antigen-antibody complex to the platelet Fc receptor was not responsible, as Fab and F(ab')2 fragments of one of the antibodies were as effective as intact antibody, and as neither heat-aggregated IgG nor a polyclonal antibody to plasma factor IX inhibited retention. F(ab')2 fragments of 6D1, an antibody to platelet GP Ib that prevents binding of vWf to platelets, also inhibited the second phase of retention. An antibody that inhibits binding of fibrinogen and vWf to GP IIb/IIIa (LJ-CP8) inhibited both the first and second stages of retention, whereas LJ-P5, an antibody that inhibits only the binding of vWf to GP IIb/IIIa, caused slight inhibition of retention when normal or afibrinogenemic blood was used as blood B and was reported to cause only partial inhibition of ADP- induced platelet aggregation in this afibrinogenemic patient. The results suggest that vWf is altered during rapid passage of blood through the glass-bead column so that it attaches to GP Ib, exposing GP IIb/IIIa, which then binds the altered vWf or fibrinogen, either of which can induce platelet aggregation (platelet-platelet adhesion) and thus retention in the column.

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