Complex formed by N-linked glycoproteins (SIBLINGS) and Factor H

Abstract

The invention provides methods and compositions for exploiting the discovery that members of the small integrin-binding ligand, n-linked glycoproteins family termed SIBLINGS bind to complement Factor H, and moreover that SIBLINGS proteins, such as BSP, exist in relatively acidic forms. The methods provided can be used to detect SIBLINGS proteins in samples from subjects that are suspected of having tumors or abnormal bone turnover. The invention also provides methods of using SIBLINGS proteins to protect cells from complement mediated lysis. Finally, the discovery allows for the creation of specific binding agents that facilitate the detection of SIBLINGS proteins when they are associated with Factor H.

1 - 14 . (canceled)  
     
     
         15 . A composition comprising a specific binding agent which specifically binds at least one SIBLINGS protein when the SIBLINGS protein is complexed with Factor H.  
     
     
         16 . The composition of  claim 15  wherein the specific binding agent is a monoclonal antibody.  
     
     
         17 . The composition of  claim 16  wherein the monoclonal antibody specifically recognizes the binds an exposed portion of the SIBLINGS protein when the SIBLINGS protein is complexed with a Factor H protein.  
     
     
         18 . A hybridoma which expresses the monoclonal antibody of  claim 17 .  
     
     
         19 . (canceled)  
     
     
         20 . A method of making the monoclonal antibody of  claim 16 , comprising presenting an antigen which is unique to a SIBLINGS/Factor H complex to a subject.  
     
     
         21 . An antibody made by the method of  claim 20 .  
     
     
         22 - 23 . (canceled)  
     
     
         24 . A purified relatively acidic BSP produced by an organism of claim  23 .  
     
     
         25 . A method of conferring protection from a complement mediated immune response to a subject, the method comprising providing within a body a supply of a protective amount of a protein selected from the group consisting of a SIBLINGS protein and a biologically active fragment of a SIBLINGS protein, sufficient to protect the subject from a complement immune response by association with the protein.  
     
     
         26 . A method of conferring protection from complement mediated lysis to a cell, the method comprising: 
 providing a vector encoding at least one biologically active SIBLINGS protein;    transforming the cell with the vector, wherein the resulting transformed cell expresses the biologically active SIBLINGS protein, and such expression confers resistance to complement mediated lysis to the cell.    
     
     
         27 . The method of  claim 25 , wherein the SIBLINGS protein is BSP.  
     
     
         28 . The method of  claim 25 , wherein the SIBLINGS protein is OPN.  
     
     
         29 . The method of  claim 25 , wherein the SIBLINGS protein is DMP1.  
     
     
         30 . The method of  claim 25 , wherein the SIBLINGS protein is DSPP.  
     
     
         31 . The method of  claim 26  wherein the cell is a cell found in a graft.  
     
     
         32 . The method of  claim 26  wherein the cell is bone marrow cell.  
     
     
         33 - 34 . (canceled)  
     
     
         36 - 45 . (canceled)