scholarly journals The contact activation mechanism in human plasma: activation induced by dextran sulfate

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1225-1233 ◽  
Author(s):  
F van der Graaf ◽  
FJ Keus ◽  
RA Vlooswijk ◽  
BN Bouma
Keyword(s):  
Human Plasma ◽  
Dextran Sulfate ◽  
Activation Mechanism ◽  
Factor Xii ◽  
Contact Activation ◽  
Prolonged Incubation ◽  
Normal Plasma ◽  
Essential Components ◽  
Factor Xiia ◽  
Kallikrein Activity

Abstract Incubation of normal human plasma with dextran sulfate for 7 min at 4 degrees C generates kallikrein amidolytic activity. No kallikrein activity is generated in factor XII or prekallikrein-deficient plasma and only small amounts (8%) in high molecular weight (HMW) kininogen- deficient plasma. Addition of specific antisera directed against prekallikrein or HMW kininogen to normal plasma blocked the generation of kallikrein activity by dextran sulfate. Thus, factor XII, prekallikrein, and HMW kininogen are essential components for optimal activation of prekallikrein. The role of limited proteolysis in the activation of prekallikrein induced by dextran sulfate was studied by adding 125I-prekallikrein to plasma. The generation of kallikrein activity paralleled the proteolytic cleavage of prekallikrein as judged on SDS gels in the presence of reducing agents. The same cleavage fragments were observed as obtained by activation of purified prekallikrein by beta-factor-XIIa. Addition of 131I-HMW kininogen and 125I-factor XII or 131I-HMW kininogen and 125I-prekallikrein to normal plasma followed by activation with dextran sulfate and analysis on SDS gels indicated that the observed cleavage of prekallikrein and HMW kininogen is fast compared to the observed cleavage of factor XII, which is much slower and less extensive. During the first minutes of incubation of normal plasma with dextran sulfate, mainly alpha-factor- XIIa is formed. During prolonged incubation, beta-factor-XIIa is also formed.

scholarly journals The contact activation mechanism in human plasma: activation induced by dextran sulfate

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1225-1233 ◽  
Author(s):  
F van der Graaf ◽  
FJ Keus ◽  
RA Vlooswijk ◽  
BN Bouma
Keyword(s):  
Human Plasma ◽  
Dextran Sulfate ◽  
Activation Mechanism ◽  
Factor Xii ◽  
Contact Activation ◽  
Prolonged Incubation ◽  
Normal Plasma ◽  
Essential Components ◽  
Factor Xiia ◽  
Kallikrein Activity

Incubation of normal human plasma with dextran sulfate for 7 min at 4 degrees C generates kallikrein amidolytic activity. No kallikrein activity is generated in factor XII or prekallikrein-deficient plasma and only small amounts (8%) in high molecular weight (HMW) kininogen- deficient plasma. Addition of specific antisera directed against prekallikrein or HMW kininogen to normal plasma blocked the generation of kallikrein activity by dextran sulfate. Thus, factor XII, prekallikrein, and HMW kininogen are essential components for optimal activation of prekallikrein. The role of limited proteolysis in the activation of prekallikrein induced by dextran sulfate was studied by adding 125I-prekallikrein to plasma. The generation of kallikrein activity paralleled the proteolytic cleavage of prekallikrein as judged on SDS gels in the presence of reducing agents. The same cleavage fragments were observed as obtained by activation of purified prekallikrein by beta-factor-XIIa. Addition of 131I-HMW kininogen and 125I-factor XII or 131I-HMW kininogen and 125I-prekallikrein to normal plasma followed by activation with dextran sulfate and analysis on SDS gels indicated that the observed cleavage of prekallikrein and HMW kininogen is fast compared to the observed cleavage of factor XII, which is much slower and less extensive. During the first minutes of incubation of normal plasma with dextran sulfate, mainly alpha-factor- XIIa is formed. During prolonged incubation, beta-factor-XIIa is also formed.

Dextran Sulfate Stimulated Fibrinolytic Activity In Whole Human Plasma: Dependence On The Contact Activation System And On 4 Urokinase-Related Antigen

1981 ◽  
Author(s):  
Lindsey A Miles ◽  
Zuleika Rothschild ◽  
John H Griffin
Keyword(s):  
Human Plasma ◽  
Fibrinolytic Activity ◽  
Dextran Sulfate ◽  
Factor Xii ◽  
Dependent Manner ◽  
Contact Activation ◽  
Prolonged Incubation ◽  
Normal Plasma ◽  
Fibrin Plate ◽  
Activation System

The generation of fibrinolytic activity in whole human plasma in the presence of dextran sulfate was studied. Plasma was preincubated with N-flufenamyl-β-alanine to remove its antiplasmin and anti activator activities and then incubated with 50 μg/ml dextran sulfate (Mr - 500,000) for 30 min at 40. The initial fibrinolytic activity in 30 min, as assessed on a 125I-fibrin plate, was equivalent to approximately 9 ng/ml purified plasmin. A fraction of goat antibodies to plasminogen blocked the fibrinolytic activity of stimulated plasma, indicating that the activity was plasminogen dependent. Plasmas genetically deficient in either prekallikrein or Factor XII (Hageman Factor) showed a diminished initial rate of generation of fibrinolytic activity in response to dextran sulfate. However, after prolonged incubation (∼3 hr) of stimulated deficient plasmas with fibrin, the fibrinolytic activity approached that of stimulated normal plasma. When normal plasma was preincubated with the gamma fraction of goat antibodies made against purified urokinase, the dextran sulfate stimulated fibrinolytic activity was markedly decreased in a dose dependent manner. The data suggest that the fibrinolytic activity stimulated in whole human plasma in the presence of dextran sulfate and N-flufenamyl-β-alanine is dependent upon proteins of the contact activation system and also upon molecules immunologically related to urokinase.

scholarly journals A monoclonal anti-human plasma prekallikrein antibody that inhibits activation of prekallikrein by factor XIIa on a surface

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1053-1062
Author(s):  
D Veloso ◽  
LD Silver ◽  
S Hahn ◽  
RW Colman
Keyword(s):  
Heavy Chain ◽  
Sodium Dodecyl ◽  
Factor Xii ◽  
Contact Activation ◽  
Fab Fragments ◽  
Microtiter Plates ◽  
Normal Plasma ◽  
Reducing Conditions ◽  
Factor Xiia ◽  
Kallikrein Activity

Of five IgGI/k murine monoclonal anti-human prekallikrein antibodies produced (MAbs), MAb 13G11 was selected for studying interaction of prekallikrein with factor XII and high-mol-wt kininogen (HMWK) during activation on a surface. Immunoblots from sodium dodecyl sulfate (SDS) gels showed that this MAb recognizes two variants (88 kd and 85 kd) of prekallikrein and kallikrein both in purified proteins and normal plasma. Under reducing conditions, kallikrein exhibits the epitope on the heavy chain but not on the light chains. Preincubation of MAb 13G11 with prekallikrein (added to prekallikrein-deficient plasma) or with normal plasma inhibited surface activation of prekallikrein 60% to 80%, as judged by amidolytic and coagulant assays. In normal plasma, inhibition by the Fab fragments was 87% of that with the entire MAb. Inhibition was not by competition between the MAb and HMWK, since neither binding of 13G11 to prekallikrein (coated on microtiter plates) was inhibited by an excess of HMWK, nor was hydrolysis of HMWK by kallikrein inhibited by 13G11. Using purified proteins in a system mimicking contact activation, inhibition by 13G11 of prekallikrein activation by factor XIIa, HMWK, and kaolin present was approximately 80%. Decreased inhibition (55% to 25%) occurred without HMWK or when kallikrein was used instead of prekallikrein. Kallikrein activity was not inhibited by 13G11 Fab fragments. These results indicate that the effect of 13G11 in plasma was neither dissociation of prekallikrein- HMWK complex nor a direct effect on kallikrein activity. Similar to the results in plasma, activation of prekallikrein, HMWK present, by factor XIIa bound to kaolin, was inhibited approximately 70% by 13G11. The results suggest a previously unrecognized site on the prekallikrein (heavy chain) required for its interaction with factor XIIa, either shared with the 13G11 epitope or located in very close proximity. The inhibition of kallikrein by intact 13G11 indicates that its binding site on the heavy chain is sterically related to the active site (light chain).

scholarly journals A monoclonal anti-human plasma prekallikrein antibody that inhibits activation of prekallikrein by factor XIIa on a surface

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1053-1062 ◽  
Author(s):  
D Veloso ◽  
LD Silver ◽  
S Hahn ◽  
RW Colman
Keyword(s):  
Heavy Chain ◽  
Sodium Dodecyl ◽  
Factor Xii ◽  
Contact Activation ◽  
Fab Fragments ◽  
Microtiter Plates ◽  
Normal Plasma ◽  
Reducing Conditions ◽  
Factor Xiia ◽  
Kallikrein Activity

Abstract Of five IgGI/k murine monoclonal anti-human prekallikrein antibodies produced (MAbs), MAb 13G11 was selected for studying interaction of prekallikrein with factor XII and high-mol-wt kininogen (HMWK) during activation on a surface. Immunoblots from sodium dodecyl sulfate (SDS) gels showed that this MAb recognizes two variants (88 kd and 85 kd) of prekallikrein and kallikrein both in purified proteins and normal plasma. Under reducing conditions, kallikrein exhibits the epitope on the heavy chain but not on the light chains. Preincubation of MAb 13G11 with prekallikrein (added to prekallikrein-deficient plasma) or with normal plasma inhibited surface activation of prekallikrein 60% to 80%, as judged by amidolytic and coagulant assays. In normal plasma, inhibition by the Fab fragments was 87% of that with the entire MAb. Inhibition was not by competition between the MAb and HMWK, since neither binding of 13G11 to prekallikrein (coated on microtiter plates) was inhibited by an excess of HMWK, nor was hydrolysis of HMWK by kallikrein inhibited by 13G11. Using purified proteins in a system mimicking contact activation, inhibition by 13G11 of prekallikrein activation by factor XIIa, HMWK, and kaolin present was approximately 80%. Decreased inhibition (55% to 25%) occurred without HMWK or when kallikrein was used instead of prekallikrein. Kallikrein activity was not inhibited by 13G11 Fab fragments. These results indicate that the effect of 13G11 in plasma was neither dissociation of prekallikrein- HMWK complex nor a direct effect on kallikrein activity. Similar to the results in plasma, activation of prekallikrein, HMWK present, by factor XIIa bound to kaolin, was inhibited approximately 70% by 13G11. The results suggest a previously unrecognized site on the prekallikrein (heavy chain) required for its interaction with factor XIIa, either shared with the 13G11 epitope or located in very close proximity. The inhibition of kallikrein by intact 13G11 indicates that its binding site on the heavy chain is sterically related to the active site (light chain).

scholarly journals Properties of sulfatides in factor-XII-dependent contact activation

Blood ◽  
1982 ◽  
Vol 59 (1) ◽  
pp. 69-75 ◽  
Author(s):  
G Tans ◽  
JH Griffin
Keyword(s):  
Normal Values ◽  
Limited Proteolysis ◽  
Factor Xii ◽  
Contact Activation ◽  
Amidolytic Activity ◽  
Prolonged Incubation ◽  
Coagulant Activity ◽  
Plasma Factor ◽  
Normal Human ◽  
Kallikrein Activity

Abstract Incubation of normal human plasma with low amounts of sulfatides resulted in the initiation of intrinsic coagulation and the appearance of kallikrein activity. The optimal initiation of procoagulant and kallikrein amidolytic activity was dependent on the presence of factor XII, high molecular weight kininogen, and prekallikrein. Since the activated partial thromboplastin clotting times in prekallikrein- deficient plasma approach normal values upon prolonged incubation with kaolin, this phenomenon of autocorrection was studied and found to be even more pronounced in the presence of sulfatides. Autocorrection was essentially completed in 5 min in the presence of sulfatides, whereas a preincubation of 15–20 min was required in the presence of kaolin. The limited proteolysis of 125I-factor XII in plasma during incubation with activating material or during clotting was determined. Cleavage of factor XII was more rapid and more extensive in the presence of sulfatides than in the presence of kaolin. In prekallikrein-deficient plasma, factor XII cleavage was completed within 5 min in the presence of sulfatides and within 15 min in the presence of kaolin. Thus, the appearance of factor-XII-dependent coagulant activity correlates with the limited proteolysis of factor XII when normal or prekallikrein- deficient plasma is activated by sulfatides or kaolin.

scholarly journals Monoclonal antibody to human high-molecular-weight kininogen recognizes its prekallikrein binding site and inhibits its coagulant activity

Blood ◽  
1989 ◽  
Vol 74 (2) ◽  
pp. 695-702 ◽  
Author(s):  
SR Reddigari ◽  
AP Kaplan
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Binding Site ◽  
Human Plasma ◽  
Light Chain ◽  
Dextran Sulfate ◽  
High Molecular Weight Kininogen ◽  
Contact Activation ◽  
Normal Plasma ◽  
Coagulant Activity

We developed a mouse monoclonal antibody (MoAb 115–21) to human high- molecular-weight kininogen (HK) that recognizes its prekallikrein binding site (residues 565 through 595 of HK). The corresponding synthesized 31-amino acid peptide (peptide IV) was recently shown to retain native HK's prekallikrein binding property. The same peptide bound factor XI also, although less avidly. Our MoAb recognizes purified HK, peptide IV, and the light chain moiety of HK (where the peptide IV resides), as shown by enzyme-linked immunosorbent assay (ELISA) and Western blotting experiments. The apparent dissociation constant for the HK and MoAb 115–21 interaction was 2.2 nmol/L. It does not recognize low-molecular-weight kininogen (LK) with which HK shares its heavy chain moiety or any antigens in human plasma congenitally deficient in kininogens. The binding of MoAb 115–21 to purified light chain of HK was competitively inhibited by peptide IV. In addition, the antibody inhibits HK-dependent clotting activity of normal human plasma and dextran sulfate-mediated activation of prekallikrein in plasma and retards cleavage of HK in normal plasma after contact activation with dextran sulfate. Also, purified Fab fragments of MoAb 115–21 inhibited the HK-dependent coagulant activity and dextran sulfate-mediated prekallikrein activation in normal plasma. Since the kd for HK-MoAb 115– 21 interaction is ten times lower than that of HK-prekallikrein, our data suggest that binding of MoAb 115–21 to HK's peptide IV site increases the free prekallikrein concentration in plasma and thus results in the decreased efficiency of factor XIIa-mediated activation of prekallikrein. Decreased levels of kallikrein thus formed may be responsible for the inhibition of HK-dependent clotting activity and the decrease in rate and extent of HK cleavage in normal plasma on contact activation with dextran sulfate. MoAb 115–21 may thus prove very useful, especially with its high affinity for HK, in further delineation of the role of HK and prekallikrein in contact activation and kinin-related human pathology.

scholarly journals Demonstration and mode of action of an inhibitor for activated Hageman factor (factor XIIa) of the intrinsic blood coagulation pathway from Schistosoma mansoni

Blood ◽  
1977 ◽  
Vol 49 (4) ◽  
pp. 619-633
Author(s):  
VC Tsang ◽  
RT Damian
Keyword(s):  
Schistosoma Mansoni ◽  
Anticoagulant Activity ◽  
Factor Xii ◽  
Contact Activation ◽  
Factor Xi ◽  
Heat Stable ◽  
Normal Plasma ◽  
Factor Xiia ◽  
Factor Xia ◽  
Coagulation Pathway

An anticoagulant activity from adult Schistosoma mansoni whole worm homogenate is described. The inhibitor appears to be specific for the contact activation step of the intrinsic pathway. Experiments with both human and mouse plasmas have defined the specificity of the inhibitor as follows: (1) It lengthens the partial thromboplastin time of normal plasma. (2) It has no effect on the prothombin time and Russell's viper venom time of normal plasma. (3) Preactivation of normal plasma by a contact activator such as Celite eliminates essentially all inhibitory activity. (4) The inhibitor appears to be heat stable and can be precipitated by centrifugation above 27,000 g. (5) The inhibitor has no effect on the activation of factor XII by Celite. (6) The activation of factor XI by factor XIIa, however, is inhibited by the schistosomal inhibitor. The above data are consistent with the view that S. mansoni adults possess an anticoagulant that is capable of specifically inhibiting the conversion of factor XI to factor XIa by factor XIIa.

scholarly journals Mechanism of transient adsorption of fibrinogen from plasma to solid surfaces: role of the contact and fibrinolytic systems

Blood ◽  
1988 ◽  
Vol 71 (4) ◽  
pp. 932-939 ◽  
Author(s):  
JL Brash ◽  
CF Scott ◽  
P ten Hove ◽  
P Wojciechowski ◽  
RW Colman
Keyword(s):  
Solid Surfaces ◽  
Factor Xii ◽  
Contact Activation ◽  
Transient Detection ◽  
Normal Plasma ◽  
Plasma Factor ◽  
Factor Xiia ◽  
Factor Xia ◽  
Specific Proteins

The transient detection of fibrinogen on surfaces has been described (Vroman effect) and high-mol-wt kininogen (HK) has been shown to play a role in this reaction. In this study, we attempted to identify the form of HK responsible for preventing detection of the fibrinogen initially adsorbed from plasma to various artificial surfaces and to determine if other plasma components were involved. We compared 125I-fibrinogen adsorption in the presence of normal plasma to plasma deficient in specific proteins. On all surfaces tested, we found that fibrinogen was displaced from the surface. The extent of displacement was greatly reduced, however, but not eliminated in HK-deficient plasma. Factor XII- deficient plasma also showed reduced fibrinogen displacement. These data indicate that HK can actually displace fibrinogen; however, factor XII, or a factor XII-mediated reaction also appears to be necessary for this displacement to occur. Furthermore, when normal plasma was first subjected to extensive contact activation by dextran sulfate, during which the HK was extensively degraded to components smaller than the light chain (as assessed by Western blotting), we observed greatly reduced displacement of fibrinogen. Extensive contact activation of Factor XI-deficient plasma failed to show low-mol-wt derivatives, however, and displacement of fibrinogen was similar to normal plasma that had not undergone extensive activation. These data indicate that HKa (active cofactor produced during contact activation by factor XIIa or kallikrein) is primarily responsible for displacing fibrinogen, and that HKi (inactive cofactor generated by factor XIa) cannot displace fibrinogen. The fibrinogen from all plasma samples looked similar by Western blot analysis, suggesting that fibrinogenolysis was not a component of the Vroman effect. In addition, experiments performed with plasma prechromatographed on lysine agarose showed that a lysine- agarose adsorbable protein may be minimally involved in fibrinogen desorption and a synergism may exist between HK and that protein.

scholarly journals Demonstration and mode of action of an inhibitor for activated Hageman factor (factor XIIa) of the intrinsic blood coagulation pathway from Schistosoma mansoni

Blood ◽  
1977 ◽  
Vol 49 (4) ◽  
pp. 619-633 ◽  
Author(s):  
VC Tsang ◽  
RT Damian
Keyword(s):  
Schistosoma Mansoni ◽  
Anticoagulant Activity ◽  
Factor Xii ◽  
Contact Activation ◽  
Factor Xi ◽  
Heat Stable ◽  
Normal Plasma ◽  
Factor Xiia ◽  
Factor Xia ◽  
Coagulation Pathway

Abstract An anticoagulant activity from adult Schistosoma mansoni whole worm homogenate is described. The inhibitor appears to be specific for the contact activation step of the intrinsic pathway. Experiments with both human and mouse plasmas have defined the specificity of the inhibitor as follows: (1) It lengthens the partial thromboplastin time of normal plasma. (2) It has no effect on the prothombin time and Russell's viper venom time of normal plasma. (3) Preactivation of normal plasma by a contact activator such as Celite eliminates essentially all inhibitory activity. (4) The inhibitor appears to be heat stable and can be precipitated by centrifugation above 27,000 g. (5) The inhibitor has no effect on the activation of factor XII by Celite. (6) The activation of factor XI by factor XIIa, however, is inhibited by the schistosomal inhibitor. The above data are consistent with the view that S. mansoni adults possess an anticoagulant that is capable of specifically inhibiting the conversion of factor XI to factor XIa by factor XIIa.

scholarly journals Mechanism of transient adsorption of fibrinogen from plasma to solid surfaces: role of the contact and fibrinolytic systems

Blood ◽  
1988 ◽  
Vol 71 (4) ◽  
pp. 932-939 ◽  
Author(s):  
JL Brash ◽  
CF Scott ◽  
P ten Hove ◽  
P Wojciechowski ◽  
RW Colman
Keyword(s):  
Solid Surfaces ◽  
Factor Xii ◽  
Contact Activation ◽  
Transient Detection ◽  
Normal Plasma ◽  
Plasma Factor ◽  
Factor Xiia ◽  
Factor Xia ◽  
Specific Proteins

Abstract The transient detection of fibrinogen on surfaces has been described (Vroman effect) and high-mol-wt kininogen (HK) has been shown to play a role in this reaction. In this study, we attempted to identify the form of HK responsible for preventing detection of the fibrinogen initially adsorbed from plasma to various artificial surfaces and to determine if other plasma components were involved. We compared 125I-fibrinogen adsorption in the presence of normal plasma to plasma deficient in specific proteins. On all surfaces tested, we found that fibrinogen was displaced from the surface. The extent of displacement was greatly reduced, however, but not eliminated in HK-deficient plasma. Factor XII- deficient plasma also showed reduced fibrinogen displacement. These data indicate that HK can actually displace fibrinogen; however, factor XII, or a factor XII-mediated reaction also appears to be necessary for this displacement to occur. Furthermore, when normal plasma was first subjected to extensive contact activation by dextran sulfate, during which the HK was extensively degraded to components smaller than the light chain (as assessed by Western blotting), we observed greatly reduced displacement of fibrinogen. Extensive contact activation of Factor XI-deficient plasma failed to show low-mol-wt derivatives, however, and displacement of fibrinogen was similar to normal plasma that had not undergone extensive activation. These data indicate that HKa (active cofactor produced during contact activation by factor XIIa or kallikrein) is primarily responsible for displacing fibrinogen, and that HKi (inactive cofactor generated by factor XIa) cannot displace fibrinogen. The fibrinogen from all plasma samples looked similar by Western blot analysis, suggesting that fibrinogenolysis was not a component of the Vroman effect. In addition, experiments performed with plasma prechromatographed on lysine agarose showed that a lysine- agarose adsorbable protein may be minimally involved in fibrinogen desorption and a synergism may exist between HK and that protein.

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