scholarly journals Inhibition of human coagulation factor VIII by monoclonal antibodies. Mapping of functional epitopes with the use of recombinant factor VIII fragments

1989 ◽  
Vol 263 (1) ◽  
pp. 187-194 ◽  
Author(s):  
A Leyte ◽  
K Mertens ◽  
B Distel ◽  
R F Evers ◽  
M J M De Keyzer-Nellen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Factor Viii ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Procoagulant Activity ◽  
Coagulation Factor Viii ◽  
Coagulation Cascade ◽  
Restriction Enzyme Digestion ◽  
Proteolytic Activation

The epitopes of four monoclonal antibodies against coagulation Factor VIII were mapped with the use of recombinant DNA techniques. Full-length Factor VIII cDNA and parts thereof were inserted into the vector pSP64, permitting transcription in vitro with the use of a promoter specific for SP6 RNA polymerase. Factor VIII DNA inserts were truncated from their 3′-ends by selective restriction-enzyme digestion and used as templates for ‘run-off’ mRNA synthesis. Translation in vitro with rabbit reticulocyte lysate provided defined radiolabelled Factor VIII fragments for immunoprecipitation studies. Two antibodies are shown to be directed against epitopes on the 90 kDa chain of Factor VIII, between residues 712 and 741. The 80 kDa chain appeared to contain the epitopes of the other two antibodies, within the sequences 1649-1778 and 1779-1840 respectively. The effect of antibody binding to these sequences was evaluated at two distinct levels within the coagulation cascade. Both Factor VIII procoagulant activity and Factor VIII cofactor function in Factor Xa generation were neutralized upon binding to the region 1779-1840. The antibodies recognizing the region 713-740 or 1649-1778, though interfering with Factor VIII procoagulant activity, did not inhibit in Factor Xa generation. These findings demonstrate that antibodies that virtually inhibit Factor VIII in coagulation in vitro are not necessarily directed against epitopes involved in Factor VIII cofactor function. Inhibition of procoagulant activity rather than of cofactor function itself may be explained by interference in proteolytic activation of Factor VIII. This hypothesis is in agreement with the localization of the epitopes in the proximity of thrombin-cleavage or Factor Xa-cleavage sites.

Clinical cases of using coagulation factor VIII with von Willebrand factor in parturient women with type III von Willebrand disease

2020 ◽  
Author(s):  
И.В. Куртов ◽  
Е.С. Фатенкова ◽  
Н.А. Юдина ◽  
А.М. Осадчук ◽  
И.Л. Давыдкин
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Coagulation Factor Viii ◽  
Vitro Fertilization ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

Болезнь Виллебранда (БВ) может представлять определенные трудности у рожениц с данной патологией. Приведены 2 клинических примера использования у женщин с БВ фактора VIII свертывания крови с фактором Виллебранда, показана эффективность и безопасность их применения. У одной пациентки было также показано использование фактора свертывания крови VIII с фактором Виллебранда во время экстракорпорального оплодотворения. Von Willebrand disease presents a certain hemostatic problem among parturients. This article shows the effectiveness and safety of using coagulation factor VIII with von Willebrand factor for the prevention of bleeding in childbirth in 2 patients with type 3 von Willebrand disease. In one patient, the use of coagulation factor VIII with von Willebrand factor during in vitro fertilization was also shown.

Rational design of small molecules targeting the C2 domain of coagulation factor VIII

Blood ◽  
2014 ◽  
Vol 123 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Gerry A. F. Nicolaes ◽  
Mahesh Kulharia ◽  
Jan Voorberg ◽  
Paul H. Kaijen ◽  
Aleksandra Wroblewska ◽  
...  
Keyword(s):  
Factor Viii ◽  
Small Molecules ◽  
Rational Design ◽  
Coagulation Factor ◽  
Coagulation Factor Viii ◽  
C2 Domain ◽  
Key Points ◽  
Thrombin Formation

Key Points Novel small molecules have been identified that specifically target FVIII. These small molecules are able to reduce in vitro thrombin formation in full blood.

scholarly journals Protein residue network analysis reveals fundamental properties of the human coagulation factor VIII

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tiago J. S. Lopes ◽  
Ricardo Rios ◽  
Tatiane Nogueira ◽  
Rodrigo F. Mello
Keyword(s):  
Factor Viii ◽  
Treatment Options ◽  
Coagulation Factor ◽  
Interaction Network ◽  
Biological Properties ◽  
Coagulation Factor Viii ◽  
Coagulation Disorder ◽  
Residue Interaction ◽  
Derived Properties

AbstractHemophilia A is an X-linked inherited blood coagulation disorder caused by the production and circulation of defective coagulation factor VIII protein. People living with this condition receive either prophylaxis or on-demand treatment, and approximately 30% of patients develop inhibitor antibodies, a serious complication that limits treatment options. Although previous studies performed targeted mutations to identify important residues of FVIII, a detailed understanding of the role of each amino acid and their neighboring residues is still lacking. Here, we addressed this issue by creating a residue interaction network (RIN) where the nodes are the FVIII residues, and two nodes are connected if their corresponding residues are in close proximity in the FVIII protein structure. We studied the characteristics of all residues in this network and found important properties related to disease severity, interaction to other proteins and structural stability. Importantly, we found that the RIN-derived properties were in close agreement with in vitro and clinical reports, corroborating the observation that the patterns derived from this detailed map of the FVIII protein architecture accurately capture the biological properties of FVIII.

The Functional Defect of Factor VIII Leiden, a Genetic Variant of Coagulation Factor VIII

1985 ◽  
Vol 54 (03) ◽  
pp. 650-653 ◽  
Author(s):  
K Mertens ◽  
A van Wijngaarden ◽  
R M Bertina ◽  
J J Veltkamp
Keyword(s):  
Factor Viii ◽  
Genetic Variant ◽  
Intrinsic Factor ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Coagulation Factor Viii ◽  
Factor X ◽  
Plasma Factor ◽  
Functional Defect ◽  
Factor X Activating Complex

SummaryFactor VIII Leiden is a genetic variant of coagulation factor VIII which has been detected in the plasma of a patient with mild haemophilia A. In this patient’s plasma factor VIII procoagulant antigen was in 5-fold excess over factor VIII procoagulant activity, indicating the presence of an abnormal factor VIII molecule. The variant factor VIII was isolated from the patient’s plasma, and its functional properties were studied in a factor X-activating system consisting of purified components. The isolated factor VIII Leiden was normally activated by factor Xa and by thrombin, but the activity of the factor Villa was about 3% of normal. The defect of factor Villa Leiden was studied by comparison with normal factor Villa in kinetic experiments of factor Xa formation. The results support the hypothesis that factor Villa Leiden has a reduced affinity for phospholipid-bound factor IXa in the intrinsic factor X-activating complex.

Coagulation cascade proteases and tissue fibrosis

2002 ◽  
Vol 30 (2) ◽  
pp. 194-200 ◽  
Author(s):  
R. C. Chambers ◽  
G. J. Laurent
Keyword(s):  
Growth Factor ◽  
Factor Xa ◽  
Tissue Growth ◽  
In Vivo Studies ◽  
Coagulation Cascade ◽  
Proteolytic Activation ◽  
Surface Receptors ◽  
Relative Contribution

Fibrotic disorders of the liver, kidney and lung are associated with excessive deposition of extracellular matrix proteins and ongoing coagulation-cascade activity. In addition to their critical roles in blood coagulation, thrombin and the immediate upstream coagulation proteases, Factors Xa and VIIa, influence numerous cellular responses that may play critical roles in subsequent inflammatory and tissue repair processes in vascular and extra-vascular compartments. The cellular effects of these proteases are mediated via proteolytic activation of a novel family of cell-surface receptors, the protease-activated receptors (PAR-1, −2, −3 and −4). Although thrombin is capable of activating PAR-1, −3 and −4, there is accumulating in vitro evidence that the profibrotic effects of thrombin are predominantly mediated via PAR-1. Factor Xa is capable of activating PAR-1 and PAR-2, but its mitogenic effects for fibroblasts are similarly mediated via PAR-1. These proteases do not exert their profibrotic effects directly, but act via the induction of potent fibrogenic mediators, such as platelet-derived growth factor and connective tissue growth factor. In vivo studies using proteolytic inhibitors, PAR-1 antagonists and PAR-1-deficient mice have provided evidence that coagulation proteases play a key role in tissue inflammation and in a number of vascular pathologies associated with hyperproliferation of smooth muscle cells. More recently, coagulation proteases have also been shown to play a role in the pathogenesis of fibrosis but the relative contribution of their cellular versus their procoagulant effects awaits urgent evaluation in vivo. These studies will be informative in determining the potential application of PAR-1 antagonists as antifibrotic agents.

scholarly journals A Macroglobulin with Inhibitory Activity Against Coagulation Factor VIII

Blood ◽  
1970 ◽  
Vol 35 (3) ◽  
pp. 370-376 ◽  
Author(s):  
P. A. CASTALDI ◽  
R. PENNY
Keyword(s):  
Factor Viii ◽  
Specific Activity ◽  
Coagulation Factor ◽  
Coagulation Factor Viii ◽  
Clotting Factor ◽  
Factor Deficiency ◽  
Spontaneous Correction ◽  
Characteristic Features

Abstract Deficiency of coagulation factor VIII occurred in a patient with a monoclonal gamma-M protein and characteristic features of Waldenström’s macroglobulinemia. The protein, found to contain lambda light chains, had specific activity against normal factor VIII that was reversible by reduction with 2-mercaptoethanol. Spontaneous correction of the clotting factor deficiency occurred during treatment. It is suggested that the macroglobulin in this patient removed or masked factor VIII by adsorption and that alteration of the protein in vitro by mercaptoethanol and in vivo by treatment removed this capacity.

scholarly journals Functional assembly of intrinsic coagulation proteases on monocytes and platelets. Comparison between cofactor activities induced by thrombin and factor Xa.

1992 ◽  
Vol 176 (1) ◽  
pp. 27-35 ◽  
Author(s):  
M P McGee ◽  
L C Li ◽  
M Hensler
Keyword(s):  
Factor Viii ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Coagulation Cascade ◽  
Factor X ◽  
Regulatory Pathways ◽  
Factor Ixa ◽  
Factor Viiia ◽  
Human Factor Viii

Generation of coagulation factor Xa by the intrinsic pathway protease complex is essential for normal activation of the coagulation cascade in vivo. Monocytes and platelets provide membrane sites for assembly of components of this protease complex, factors IXa and VIII. Under biologically relevant conditions, expression of functional activity by this complex is associated with activation of factor VIII to VIIIa. In the present studies, autocatalytic regulatory pathways operating on monocyte and platelet membranes were investigated by comparing the cofactor function of thrombin-activated factor VIII to that of factor Xa-activated factor VIII. Reciprocal functional titrations with purified human factor VIII and factor IXa were performed at fixed concentrations of human monocytes, CaCl2, factor X, and either factor IXa or factor VIII. Factor VIII was preactivated with either thrombin or factor Xa, and reactions were initiated by addition of factor X. Rates of factor X activation were measured using chromogenic substrate specific for factor Xa. The K1/2 values, i.e., concentration of factor VIIIa at which rates were half maximal, were 0.96 nM with thrombin-activated factor VIII and 1.1 nM with factor Xa-activated factor VIII. These values are close to factor VIII concentration in plasma. The Vsat, i.e., rates at saturating concentrations of factor VIII, were 33.3 and 13.6 nM factor Xa/min, respectively. The K1/2 and Vsat values obtained in titrations with factor IXa were not significantly different from those obtained with factor VIII. In titrations with factor X, the values of Michaelis-Menten coefficients (Km) were 31.7 nM with thrombin-activated factor VIII, and 14.2 nM with factor Xa-activated factor VIII. Maximal rates were 23.4 and 4.9 nM factor Xa/min, respectively. The apparent catalytic efficiency was similar with either form of factor VIIIa. Kinetic profiles obtained with platelets as a source of membrane were comparable to those obtained with monocytes. These kinetic profiles are consistent with a 1:1 stoichiometry for the functional interaction between cofactor and enzyme on the surface of monocytes and platelets. Taken together, these results indicate that autocatalytic pathways connecting the extrinsic, intrinsic, and common coagulation pathways can operate efficiently on the monocyte membrane.

scholarly journals Characterization of Factor VIII-Inhibitor By-Passing Activity (FEIBA)

1977 ◽  
Author(s):  
K. Hess ◽  
N. Shih ◽  
G. Tishkoff
Keyword(s):  
Factor Viii ◽  
Factor Xa ◽  
Factor Ix ◽  
Coagulation Cascade ◽  
Factor Viii Inhibitor ◽  
Factor X ◽  
Clotting Factors ◽  
Human Factor Ix ◽  
Viii Inhibitor

In an attempt to identify the thrombogenic factor in human factor IX concentrates, we have studied the role of trace quantities of activated clotting factors employing an assay that compares the Factor VIII-like activity of IX concentrates with the ability of these products to restore to normal the abnormal activated partial thromboplastin time (APTT) of Factor VIII inhibitor plasma after 1 minute and 40 minute incubation. A coagulant activity (FEIBA) was evident when partially purified Factors X and II were combined in vitro. Factor Xa (4 × 10-4 u) plus Factor II gave negative results. Factor IIa (5.5 × 10-2u), when combined with Factor X, generated FEIBA. Activated clotting factors (Xa, IIa) when tested alone, at comparable levels, were devoid of FEIBA. Our results suggest a mechanism, distinct from activated clotting factors, that can effectively by-pass the Factor VIII defect in the coagulation cascade. The proposed mechanism appears to also by-pass the normal inhibitory properties (i.e., antithrombin III) of human blood.

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