scholarly journals Analyses of the In Vivo Trafficking of Stoichiometric Doses of an Anti-Complement Receptor 1/2 Monoclonal Antibody Infused Intravenously in Mice

2004 ◽  
Vol 173 (4) ◽  
pp. 2297-2306 ◽  
Author(s):  
Emily C. Whipple ◽  
Ryan S. Shanahan ◽  
Andrew H. Ditto ◽  
Ronald P. Taylor ◽  
Margaret A. Lindorfer
Keyword(s):  
Monoclonal Antibody ◽  
Complement Receptor ◽  
Complement Receptor 1

scholarly journals Deficiency of decay-accelerating factor and complement receptor 1–related gene/protein y on murine platelets leads to complement-dependent clearance by the macrophage phagocytic receptor CRIg

Blood ◽  
2008 ◽  
Vol 112 (4) ◽  
pp. 1109-1119 ◽  
Author(s):  
David D. Kim ◽  
Takashi Miwa ◽  
Yuko Kimura ◽  
Reto A. Schwendener ◽  
Menno van Lookeren Campagne ◽  
...  
Keyword(s):  
Human Platelets ◽  
Transfer Model ◽  
Complement Receptor ◽  
Dependent Manner ◽  
Complement Receptors ◽  
Related Gene ◽  
Decay Accelerating Factor ◽  
Gene Ablation ◽  
Complement Receptor 1

Abstract Complement activation on human platelets is known to cause platelet degranulation and activation. To evaluate how normal platelets escape complement attack in vivo, we studied the fate of murine platelets deficient in 2 membrane complement regulatory proteins using an adoptive transfer model. We show here that deficiency of either decay-accelerating factor (DAF) or complement receptor 1–related gene/protein y (Crry) on murine platelets was inconsequential, whereas DAF and Crry double deficiency led to rapid clearance of platelets from circu-lation in a complement- and macrophage-dependent manner. This finding contrasted with the observation on erythrocytes, where Crry deficiency alone resulted in complement susceptibility. Quantitative flow cytometry revealed that DAF and Crry were expressed at similar levels on platelets, whereas Crry expression was 3 times higher than DAF on erythrocytes. Antibody blocking or gene ablation of the newly identified complement receptor CRIg, but not complement receptor 3 (CR3), rescued DAF/Crry-deficient platelets from complement-dependent elimination. Surprisingly, deficiency of CRIg, CR3, and other known complement receptors failed to prevent Crry-deficient erythrocytes from complement-mediated clearance. These results show a critical but redundant role of DAF and Crry in platelet survival and suggest that complement-opsonized platelets and erythrocytes engage different complement receptors on tissue macrophages in vivo.

Complement receptor 1 inhibitors for prevention of immune-mediated red cell destruction: potential use in transfusion therapy

Blood ◽  
2003 ◽  
Vol 101 (12) ◽  
pp. 5046-5052 ◽  
Author(s):  
Karina Yazdanbakhsh ◽  
Stanley Kang ◽  
Daniel Tamasauskas ◽  
Dorothy Sung ◽  
Andromachi Scaradavou
Keyword(s):  
Tissue Injury ◽  
Soluble Form ◽  
Complement Receptor ◽  
Classical Pathway ◽  
Human Group ◽  
Transfusion Therapy ◽  
Complement Receptor 1 ◽  
Potential Use

AbstractActivation of complement cascade via the antibody-mediated classical pathway can initiate red blood cell (RBC) destruction, causing transfusion reactions and hemolytic anemia. In the present study, we have assessed the ability of a human recombinant soluble form of complement receptor 1 (sCR1) to inhibit complement-mediated RBC destruction in vitro and in vivo. Using an in vitro alloimmune incompatibility model, sCR1 inhibited complement activation and prevented hemolysis. Following transfusion of human group O RBCs into mice lacking detectable pre-existing antibodies against the transfused RBCs, systemic coadministration of 10 mg/kg sCR1, a dose well tolerated in human subjects for prevention of tissue injury, completely inhibited the in vivo clearance of the transfused RBCs and surface C3 deposition in the first hour after transfusion, correlating with the half-life of sCR1 in the circulation. Treatment with sCR1 increased the survival of transfused human group A RBCs in the circulation of mice with pre-existing anti-A for 2 hours after transfusion by 50%, reduced intravascular hemolysis, and lowered the levels of complement deposition (C3 and C4), but not immunoglobulin G (IgG) or IgM, on the transfused cells by 100-fold. We further identified potential functional domains in CR1 that can act to limit complement-mediated RBC destruction in vitro and in vivo. Collectively, our data highlight a potential use of CR1-based inhibitors for prevention of complement-dependent immune hemolysis.

scholarly journals In vivo inhibition of the antibody response by a complement receptor-specific monoclonal antibody.

1990 ◽  
Vol 172 (2) ◽  
pp. 665-668 ◽  
Author(s):  
B Heyman ◽  
E J Wiersma ◽  
T Kinoshita
Keyword(s):  
Antibody Response ◽  
Serum Antibody ◽  
Keyhole Limpet Hemocyanin ◽  
The Other ◽  
Rosette Formation ◽  
Complement Receptor ◽  
Primary Antibody Response ◽  
Complement Receptor 1 ◽  
Horse Red Blood Cells

BALB/c mice were injected intravenously with three different monoclonal antibodies (mAbs) specific for complement receptor 1 (CR1). Two of the mAbs crossreacted with CR2. 24 h later, the mice were immunized with horse erythrocytes or keyhole limpet hemocyanin (KLH), and the primary antibody response was measured. One of the anti-CR antibodies, 7G6, suppressed greater than 99% of the direct plaque-forming cell response against horse red blood cells (HRBC). The same antibody markedly suppressed the serum antibody responses to both HRBC and KLH. To be optimally suppressive, the mAb had to be injected before suboptimal concentrations of antigen. The other two complement receptor-specific antibodies had very moderate, if any, effects on the antibody response. 7G6 was able to downregulate CR1 and CR2 on the surface of B cells and, in addition, to inhibit rosette formation with C3d-coated sheep erythrocytes (EC3d). One of the antibodies with a weak effect downregulated only CR1. The other downregulated both CR1 and CR2, although not as efficiently as 7G6, and was unable to inhibit EC3d rosette formation. We conclude that the reason 7G6 is outstanding in its suppressive capacity is that it is the only mAb tested that functionally blocks CR2. The data suggest that CR2 is of crucial importance in the initiation of a normal antibody response to physiological concentrations of antigen.

Functional Analysis of Complement Receptor 1 Using a New Monoclonal Antibody, KuN241

Hybridoma ◽  
1995 ◽  
Vol 14 (1) ◽  
pp. 29-35 ◽  
Author(s):  
JAMES M. MATHEW ◽  
BASHOO NAZIRUDDIN ◽  
BRIAN DUFFY ◽  
MALGORZATA KRYCH ◽  
T. MOHANAKUMAR
Keyword(s):  
Monoclonal Antibody ◽  
Functional Analysis ◽  
Complement Receptor ◽  
Complement Receptor 1

scholarly journals Expression of a Functional Single-Chain Variable-Fragment Antibody against Complement Receptor 1 in Streptococcus gordonii

2008 ◽  
Vol 15 (6) ◽  
pp. 925-931 ◽  
Author(s):  
Jennifer B. Knight ◽  
Scott A. Halperin ◽  
Kenneth A. West ◽  
Song F. Lee
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Vaccine Development ◽  
Oral Vaccine ◽  
Complement Receptor ◽  
Streptococcus Gordonii ◽  
Single Chain Variable Fragment ◽  
Single Chain ◽  
Complement Receptor 1

ABSTRACT Streptococcus gordonii, an oral commensal organism, is a candidate vector for oral-vaccine development. Previous studies have shown that recombinant S. gordonii expressing heterologous antigens was weakly immunogenic when delivered intranasally. In this study, antigen was specifically targeted to antigen-presenting cells (APC) in order to potentiate antigen-APC interactions and increase the humoral immune response to the antigen. To achieve this goal, a single-chain variable-fragment (scFv) antibody against complement receptor 1 (CR1) was constructed. Anti-CR1 scFv purified from Escherichia coli was able to bind to mouse mixed lymphocytes and bone marrow-derived dendritic cells. The in vivo function of the anti-CR1 scFv protein was assessed by immunizing mice intranasally with soluble scFv and determining the immune response against the hemagglutinin (HA) peptide located on the carboxy terminus of the scFv. The serum anti-HA immunoglobulin G (IgG) immune response was dose dependent; as little as 100 ng of anti-CR1 scFv induced a significant IgG immune response, while such a response was minimal when the animals were given an unrelated scFv. The anti-CR1 scFv was expressed in S. gordonii as a secreted protein, which was functional, as it bound to dendritic cells. Mice orally colonized by the anti-CR1-secreting S. gordonii produced an anti-HA IgG immune response, indicating that such an approach can be used to increase the immune response to antigens produced by this bacterium.

The Anticoagulant Properties of a Modified Form of Protein S

1988 ◽  
Vol 60 (02) ◽  
pp. 298-304 ◽  
Author(s):  
C A Mitchell ◽  
S M Kelemen ◽  
H H Salem
Keyword(s):  
Monoclonal Antibody ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Factor Xa ◽  
Protein S ◽  
Human Neutrophil Elastase ◽  
Factor X ◽  
Sds Page

SummaryProtein S (PS) is a vitamin K-dependent anticoagulant that acts as a cofactor to activated protein C (APC). To date PS has not been shown to possess anticoagulant activity in the absence of APC.In this study, we have developed monoclonal antibody to protein S and used to purify the protein to homogeneity from plasma. Affinity purified protein S (PSM), although identical to the conventionally purified protein as judged by SDS-PAGE, had significant anticoagulant activity in the absence of APC when measured in a factor Xa recalcification time. Using SDS-PAGE we have demonstrated that prothrombin cleavage by factor X awas inhibited in the presence of PSM. Kinetic analysis of the reaction revealed that PSM competitively inhibited factor X amediated cleavage of prothrombin. PS preincubated with the monoclonal antibody, acquired similar anticoagulant properties. These results suggest that the interaction of the monoclonal antibody with PS results in an alteration in the protein exposing sites that mediate the observed anticoagulant effect. Support that the protein was altered was derived from the observation that PSM was eight fold more sensitive to cleavage by thrombin and human neutrophil elastase than conventionally purified protein S.These observations suggest that PS can be modified in vitro to a protein with APC-independent anticoagulant activity and raise the possibility that a similar alteration could occur in vivo through the binding protein S to a cellular or plasma protein.

Effects of a Monoclonal Antibody to Glycoprotein IIb/IIIa (P256) and of Enzymically Derived Fragments of P256 on Human Platelets

1991 ◽  
Vol 65 (04) ◽  
pp. 432-437 ◽  
Author(s):  
A W J Stuttle ◽  
M J Powling ◽  
J M Ritter ◽  
R M Hardisty
Keyword(s):  
Monoclonal Antibody ◽  
Flow Cytometry ◽  
Platelet Aggregation ◽  
Calcium Ions ◽  
Human Platelet ◽  
Human Platelets ◽  
In Vivo Detection ◽  
Fibrinogen Binding ◽  
Specific Antagonist

SummaryThe anti-platelet monoclonal antibody P256 is currently undergoing development for in vivo detection of thrombus. We have examined the actions of P256 and two fragments on human platelet function. P256, and its divalent fragment, caused aggregation at concentrations of 10−9−3 × 10−8 M. A monovalent fragment of P256 did not cause aggregation at concentrations up to 10−7 M. P256–induced platelet aggregation was dependent upon extracellular calcium ions as assessed by quin2 fluorescence. Indomethacin partially inhibited platelet aggregation and completely inhibited intracellular calcium mobilisation. Apyrase caused partial inhibition of aggregation. Aggregation induced by the divalent fragment was dependent upon fibrinogen and was inhibited by prostacyclin. Aggregation induced by the whole antibody was only partially dependent upon fibrinogen, but was also inhibited by prostacyclin. P256 whole antibody was shown, by flow cytometry, to induce fibrinogen binding to indomethacin treated platelets. Monovalent P256 was shown to be a specific antagonist for aggregation induced by the divalent forms. In–111–labelled monovalent fragment bound to gel-filtered platelets in a saturable and displaceable manner. Monovalent P256 represents a safer form for in vivo applications

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