Therapeutic and diagnostic domain 1 beta2GP1 polypeptides and methods of using same

Abstract

The present invention provides domain 1 β 2 GPI polypeptides, polynucleotides encoding these polypeptides, mimetics of these polypeptides, and methods using domain 1 β 2 GPI polypeptides and mimetics. Domain 1 of β 2 GPI has been shown to bind to anti-cardiolipin (β 2 GPI-dependent antiphospholipid) antibodies, which are associated with several pathologies, such as thrombosis and fetal loss. The domain 1 β 2 GPI polypeptides may be used to detect β 2 GPI-dependent antiphospholipid antibodies in a sample. The invention further provides methods of inducing tolerance using these domain 1 β 2 GPI polypeptides.

1 . A polypeptide comprising a domain 1 β 2 GPI polypeptide, wherein the polypeptide specifically binds to an β 2 GPI-dependent antiphospholipid antibody, and wherein the polypeptide does not consist of the group consisting of the polypeptide SEQ ID NO:2 ( FIG. 1 ); domains 1, 2, and 3 of β 2 GPI; and domains 1, 2, 3, and 4 of β 2 GPI.  
     
     
         2 . The polypeptide of  claim 1 , wherein the domain 1 β 2 GPI polypeptide consists of the polypeptide SEQ ID NO:4 ( FIG. 2 ).  
     
     
         3 . The polypeptide of  claim 1 , wherein the domain 1 β 2 GPI polypeptide is selected from the group consisting of SEQ ID NOS:5-12.  
     
     
         4 . The polypeptide of  claim 1 , wherein the domain 1 β 2 GPI polypeptide comprises about amino acid 1 to about amino acid 66 of SEQ ID NO:1.  
     
     
         5 . The polypeptide of  claim 1 , wherein the domain 1 β 2 GPI polypeptide comprises about amino acid 1 to about amino acid 59 of SEQ ID NO:4.  
     
     
         6 . A fusion polypeptide comprising the polypeptide of  claim 1 .  
     
     
         7 . A polymeric polypeptide comprising the polypeptide of  claim 1 .  
     
     
         8 . The polypeptide of  claim 1 , wherein the polypeptide lacks a T cell epitope, said T cell epitope capable of activating T cells in an individual having β 2 GPI dependent antiphospholipid antibodies.  
     
     
         9 . A conjugate of the polypeptide of  claim 8 .  
     
     
         10 . The conjugate of  claim 9 , wherein the conjugate comprises a label.  
     
     
         11 . The conjugate of  claim 9 , wherein the conjugate comprises a valency platform molecule.  
     
     
         12 . The conjugate of  claim 11 , wherein the platform molecule is proteinaceous.  
     
     
         13 . The conjugate of  claim 11 , wherein the platform molecule is non-proteinaceous.  
     
     
         14 . The conjugate of  claim 11 , wherein the molecular weight of a population of valency platform molecules is homogeneous.  
     
     
         15 . The conjugate of  claim 11 , wherein the platform molecule is linked to the polypeptide by a thioether bond.  
     
     
         16 . The conjugate of  claim 11 , wherein the platform molecule is linked to the polypeptide by an oxime bond.  
     
     
         17 . The conjugate of  claim 11 , wherein the platform molecule is  
       
         
           
           
               
               
           
         
       
     
     
         18 . The conjugate of  claim 11 , wherein the platform molecule is  
       
         
           
           
               
               
           
         
       
     
     
         19 . The conjugate of  claim 11 , wherein the conjugate is  
       
         
           
           
               
               
           
         
         wherein D1 is a β 2 GPI domain 1 polypeptide.  
       
     
     
         20 . The conjugate of  claim 11 , wherein the conjugate is  
       
         
           
           
               
               
           
         
         wherein D1 is a β 2 GPI domain 1 polypeptide.  
       
     
     
         21 . An isolated naturally occurring polynucleotide encoding the polypeptide of  claim 1 .  
     
     
         22 . A non-naturally occurring polynucleotide encoding the polypeptide of  claim 1 .  
     
     
         23 . An isolated naturally-occurring polynucleotide encoding the polypeptide of  claim 8 .  
     
     
         24 . A non-naturally-occurring polynucleotide encoding the polypeptide of  claim 8 .  
     
     
         25 . An expression vector comprising the polynucleotide of  claim 21 .  
     
     
         26 . A cloning vector comprising the polynucleotide of  claim 21 .  
     
     
         27 . A host cell transformed with the polynucleotide of  claim 21 .  
     
     
         28 . A mimetic of a domain 1 β 2 GPI polypeptide, wherein the mimetic specifically binds to an β 2 GPI-dependent antiphospholipid antibody to which a domain β 2 GPI polypeptide specifically binds.  
     
     
         29 . The mimetic of  claim 28 , which is a polypeptide.  
     
     
         30 . The mimetic of  claim 29 , which lacks a T cell epitope, said T cell epitope capable of activating T cells in an individual having β 2 GPI dependent antiphospholipid antibodies.  
     
     
         31 . A kit for detecting an antibody that specifically binds to a domain 1 β 2 GPI polypeptide comprising the polypeptide of  claim 1  in suitable packaging.  
     
     
         32 . A kit for detecting coagulation comprising the polypeptide of  claim 1  in suitable packaging.  
     
     
         33 . A composition comprising an effective amount of the polypeptide of  claim 8 , wherein an effective amount is an amount sufficient to induce tolerance.  
     
     
         34 . The composition of  claim 33 , further comprising a pharmaceutically acceptable excipient.  
     
     
         35 . A composition comprising an effective amount of the polypeptide of  claim 1 , wherein an effective amount is an amount sufficient to detect a β 2 GPI-dependent antiphospholipid antibody.  
     
     
         36 . A method of detecting an antibody which specifically binds to the polypeptide of  claim 1  in a sample, comprising (a) contacting antibody in the sample with the polypeptide of  claim 1  under conditions that permit the formation of a stable antigen-antibody complex; and (b) detecting stable complex formed in step (a), if any.  
     
     
         37 . The method of  claim 36 , wherein the antibody is a β 2 GPI-dependent antiphospholipid antibody.  
     
     
         38 . A method of purifying a β 2 GPI-dependent antiphospholipid antibody, comprising contacting a biological sample with the polypeptide of  claim 1  under conditions that permit the formation of a stable antigen-antibody complex, and obtaining the complex formed, if any.  
     
     
         39 . A method of inducing tolerance in an individual, comprising administering an effective amount of a composition comprising the polypeptide of  claim 8  to the individual.  
     
     
         40 . The method of  claim 39 , wherein the individual is human.  
     
     
         41 . A method of inducing tolerance in an individual, comprising administering an effective amount of a composition comprising the conjugate of  claim 11  to the individual.  
     
     
         42 . The method of  claim 41 , wherein the individual is human.  
     
     
         43 . The method of  claim 42 , wherein the polypeptide consists of the sequence from about amino acid 1 to about amino acid 60 of SEQ ID NO:4.  
     
     
         44 . A method for detecting β 2 GPI-dependent antiphospholipid antibody mediation of coagulation, comprising the steps of: 
 (a) performing a first coagulation assay using a suitable biological sample from an individual, wherein a the polypeptide of  claim 1  is added to the assay;  
 (b) performing a second coagulation assay using a suitable biological sample from the individual in the absence of the polypeptide of  claim 1;   
 (c) comparing the assay results of steps (a) and (b), wherein a difference in the results indicates β 2 GPI-dependent antiphospholipid antibody mediation of coagulation.