Fc receptor binding proteins

Abstract

This disclosure provides, inter alia, proteins that bind to FcRn, e.g., immunoglobulins that inhibit FcRn with high affinity and selectivity. The FcRn-binding proteins can be used to treat a variety of disorders including autoimmune disorders.

1 - 67 . (canceled) 
     
     
         68 . A method of modulating an FcRn activity, the method comprising:
 contacting FcRn with an antibody that binds human FcRn, thereby modulating the activity of the FcRn, wherein the antibody comprises a heavy chain (HC) immunoglobulin variable domain sequence and a light chain (LC) immunoglobulin variable domain sequence; and wherein   the HC comprises:
 a HC CDR1 comprising the amino acid sequence EYAMG (SEQ ID NO:144) or VYAMG (SEQ ID NO:156), 
 a HC CDR2 comprising the amino acid sequence SIGSSGGQTKYADSVKG (SEQ ID NO:145) or SIGSSGGPTKYADSVKG (SEQ ID NO:157), and 
 a HC CDR3 comprising the amino acid sequence LSTGELY (SEQ ID NO:146), LSIRELV (SEQ ID NO:158), LSIVDSY (SEQ ID NO:164), LSLGDSY (SEQ ID NO:170), or, LAIGDSY (SEQ ID NO:176); and 
   the LC comprises:
 a LC CDR1 comprising the amino acid sequence TGTGSDVGSYNLVS (SEQ ID NO:141), 
 a LC CDR2 comprising the amino acid sequence GDSQRPS (SEQ ID NO:142), and 
 a LC CDR3 comprising the amino acid sequence CSYAGSGIYV (SEQ ID NO:143). 
   
     
     
         69 - 110 . (canceled) 
     
     
         111 . The method of  claim 68 , wherein the FcRn is in a human subject. 
     
     
         112 . The method of  claim 68 , wherein the antibody prevents binding of the FcRn to an endogenous Ig. 
     
     
         113 . The method of  claim 68 , wherein the antibody prevents binding of the FcRn to a therapeutic antibody. 
     
     
         114 . The method of  claim 68 , wherein the binding between FcRn and the antibody occurs in an epithelial cell endosome. 
     
     
         115 . The method of  claim 68 , wherein the binding between FcRn and the antibody occurs in an endothelial cell endosome. 
     
     
         116 . The method of  claim 68 , wherein the binding between FcRn and the antibody occurs on the cell surface.