Recombinant soluble Fc receptors

Abstract

Recombinant soluble Fc receptors according to the present invention are characterized by the absence of transmembrane domains, signal peptides and glycosylation. Such Fc receptors can easily be obtained by expressing respective nucleic acids in prokaryotic host cells and renaturation of the obtained inclusion bodies, which procedure leads to a very homogenous and pure product. The products can be used for diagnostic as well as pharmaceutical applications and also for the generation of crystal structure data. Such crystal structure data can be used for the modelling of artificial molecules. A further embodiment comprises coupling the Fc receptors according to the invention to solid materials like chromatography materials that can be used to separate and/or enrich antibodies.

1 - 40 . (canceled) 
     
     
         41 - 66 . (canceled) 
     
     
         67 . A purified, crystalline, recombinantly produced, soluble Fcγ or Fcε receptor molecule, which lacks any of (i) a transmembrane domain, (ii) signal peptide, and (ii) glycosylation. 
     
     
         68 . The purified, crystalline recombinantly produced soluble Fcγ or Fcε receptor molecule of  claim 67 , which is a human receptor. 
     
     
         69 . The purified, crystalline, recombinantly produced soluble Fcγ or Fcε receptor molecule of  claim 67 , comprising an amino acid sequence set forth in SEQ. ID NO. 3 or SEQ ID NO: 4. 
     
     
         70 . A purified complex of the purified, crystalline recombinantly produced soluble Fcγ or Fcε receptor of claim  1 , and immunoglobulin. 
     
     
         71 . The purified, crystalline, recombinantly produced soluble Fcγ or Fcε receptor molecule of  claim 67 , produced by expression of said molecule in a prokaryotic cell. 
     
     
         72 . A method of identifying an Fcγ or Fcε receptor inhibitor of  claim 67 , comprising inputting, crystal structure data from said receptor into a computer modeling program to identify an inhibitor which is complementary to said receptor. 
     
     
         73 . A method for identifying or preparing an Fcγ or Fcε receptor molecule of  claim 67 , wherein said inhibitor is complementary to said molecule, comprising inputting crystalline data from said molecule into a computer aided modeling program to identify or to prepare said inhibitor. 
     
     
         74 . A method for identifying or preparing an inhibitor of the molecule of  claim 67 , comprising:
 (i) obtaining three dimensional structural data for said molecule, and   (ii) selecting or designing one of:
 (a) an inhibitor of said molecule which is complementary to an Fcγ or Fcε receptor binding site of an immunoglobulin; 
 (b) an inhibitor which is complementary to an immunoglobulin binding site of an Fcγ or Fcε receptor, and 
 (c) an antagonist or competitive Fcγ or Fcε receptor. 
   
     
     
         75 . A method for modulating interaction of an Fc receptor and an immunoglobulin molecule, comprising contacting a mixture of said Fc receptor and said immunoglobulin molecule with an inhibitor identified by the method of  claim 73  or  74 , under conditions favoring modulating interaction. 
     
     
         76 . The method of  claim 75 , wherein said inhibitor partially or completely inhibits binding and said immunoglobulin.