Compositions and methods for simultaneous bivalent and monovalent co-engagement of antigens

Abstract

Immunoglobulin compositions that simultaneously co-engage antigens, where one of the antigens is bound bivalently and the other antigen is bound monovalently. The novel immunoglobulins described preferably utilize heterodimeric Fc regions.

We claim: 
     
         1 . An antibody analog comprising:
 a) a first heavy chain and an associated light chain, wherein said first heavy and light chains form a first antigen binding site, wherein the C-terminus of the CH3 domain of said first heavy chain is covalently attached to a C-terminal variable heavy domain;   b) a second heavy chain and an associated light chain, wherein said second heavy and light chains form a second antigen binding site, wherein the C-terminus of the CH3 domain of said second heavy chain is covalently attached to a C-terminal variable light domain;   such that said C-terminal variable heavy and light domains form a third antigen binding site.   
     
     
         2 . An antibody analog according to  claim 1  wherein two of said antigen binding sites are the same and the third is different. 
     
     
         3 . An antibody analog according to  claim 1  wherein the antigen bound by said third antigen binding site is CD3. 
     
     
         4 . An antibody analog according to  claim 1  wherein the antigen bound by said third antigen binding site is FcγRIIb. 
     
     
         5 . An antibody analog according to  claim 1  wherein all three of said antigen binding sites are the same. 
     
     
         6 . An antibody analog according to  claim 1  wherein said the C-terminus of said C-terminal variable heavy domain is covalently attached to a CH1 domain and wherein said C-terminus of said C-terminal variable light domain is covalently attached to a CL domain. 
     
     
         7 . An antibody analog according to  claim 1  wherein each heavy chain comprises at least one amino acid substitution within the Fc region. 
     
     
         8 . An antibody analog according to  claim 7  wherein each heavy chain comprises a different amino acid substitution, such that a heterodimeric Fc region is more stable than a homodimeric Fc region. 
     
     
         9 . An antibody analog according to  claim 7  wherein said substitution reduces binding to at least one FcγR receptor. 
     
     
         10 . An antibody analog according to  claim 7  wherein said amino acid substitution increases binding to at least one FcγR receptor. 
     
     
         11 . An antibody analog according to  claim 7  wherein said amino acid substitution increases binding to the FcRn receptor. 
     
     
         12 . An antibody analog according to  claim 7  wherein said amino acid substitutions are selected from the group consisting of 349A, 349C, 349E, 349I, 349K, 349S, 349T, 349W, 351E, 351K, 354C, 356K, 357K, 364C, 364D, 364E, 364F, 364G, 364H, 364R, 364T, 364Y, 366D, 366K, 366S, 366W, 366Y, 368A, 368E, 368K, 368S, 370C, 370D, 370E, 370G, 370R, 370S, 370V, 392D, 392E, 394F, 394S, 394W, 394Y, 395T, 395V, 396T, 397E, 397S, 397T, 399K, 401K, 405A, 405S, 407T, 407V, 409D, 409E, 411D, 411E, 411K, and 439D. 
     
     
         13 . An antibody analog comprising:
 a) a first heavy chain comprising a variable heavy domain;   b) a second chain comprising the Fc domain of a heavy chain covalently linked to a light chain, wherein said first heavy chain and said second chain form a first antigen binding site;   wherein the C-terminus of the CH3 domain of said first heavy chain is covalently attached to a variable heavy domain and the C-terminus of the CH3 domain of said second chain is covalently attached to a variable light domain, such that said variable heavy and light domains form a second antigen binding site.   
     
     
         14 . An antibody analog according to  claim 13  wherein a CH1 domain is covalently attached to said variable heavy domain covalently attached to the CH3 domain of said first heavy chain and wherein a CL domain is covalently attached to said variable light domain covalently attached to said CH3 domain of said second chain. 
     
     
         15 . An antibody analog according to  claim 13 , wherein the wherein each of said protein chains comprises a variant CH3 domain relative to a native CH3 domain. 
     
     
         16 . An antibody analog according to  claim 15 , wherein each of said variant CH3 domains comprise different amino acid substitutions, such that a heterodimeric protein pair is more stable than a homodimeric protein pair. 
     
     
         17 . An antibody analog according to  claim 16 , wherein said substitution is selected from the group consisting of 349A, 349C, 349E, 349I, 349K, 349S, 349T, 349W, 351E, 351K, 354C, 356K, 357K, 364C, 364D, 364E, 364F, 364G, 364H, 364R, 364T, 364Y, 366D, 366K, 366S, 366W, 366Y, 368A, 368E, 368K, 368S, 370C, 370D, 370E, 370G, 370R, 370S, 370V, 392D, 392E, 394F, 394S, 394W, 394Y, 395T, 395V, 396T, 397E, 397S, 397T, 399K, 401K, 405A, 405S, 407T, 407V, 409D, 409E, 411D, 411E, 411K, and 439D, wherein numbering is according to the EU index as in Kabat.