Bispecific antibody

Abstract

Provided are bispecific antibodies comprised of a single-chain unit having specificity to an immune cell and a monovalent unit having specificity to a tumor cell or a microorganism. The single-chain unit includes a single-chain variable fragment (scFv) fused to an Fc fragment and the monovalent unit includes a light chain and heavy chain pair. Also provided are methods of preparing bispecific antibodies and pharmaceutical and diagnostic uses of these antibodies.

1 . An antibody comprising:
 (a) a monovalent unit comprising a light chain-heavy chain pair having specificity to a tumor antigen selected from the group consisting of EGFR, Her2, EpCAM, CD20, CD30, CD33, CD47, CD52, CD133, CEA, gpA33, Mucins, TAG-72, CIX, PSMA, folate-binding protein, GD2, GD3, GM2, VEGF, VEGFR, Integrin, αVβ3, α5β1, ERBB2, ERBB3, MET, IGF1R, EPHA3, TRAILR1, TRAILR2, RANKL, FAP and Tenascin, wherein the heavy chain comprises a first human or a humanized IgG1 Fc fragment; and   (b) a single-chain unit comprising a second human or a humanized IgG1 Fc fragment and a fusion peptide comprising a single-chain variable fragment (scFv) having specificity to an antigen selected from the group consisting of CD3, CD16, CD19, CD28 and CD64, wherein the scFv has Formula (I): VH-X-VL, and wherein X is a linker, and where VL is linked to the second Fc fragment, wherein the single-chain unit does not contain a CH1 domain.   
     
     
         2 . The antibody of  claim 1 , wherein the light chain is bound to the heavy chain through a disulfide bond. 
     
     
         3 . The antibody of  claim 1 , wherein the heavy chain is bound to the fusion peptide through one or more disulfide bonds. 
     
     
         4 . The antibody of  claim 1 , wherein the first Fc fragment and the second Fc fragment of the fusion peptide comprise substitutions, as compared to a wild-type antibody fragment, that form one or more ionic bonds between the first Fc fragment and the second Fc fragment. 
     
     
         5 . The antibody of  claim 4 , wherein the substitutions are pairs selected from Table 1. 
     
     
         6 . The antibody of  claim 1 , wherein the first Fc fragment and the second Fc fragment of the fusion peptide comprises substitutions, as compared to a wild-type antibody fragment, that form one or more knob-into-the-holes conformational pairing between the first Fc fragment and the second Fc fragment. 
     
     
         7 . The antibody of  claim 6 , wherein the substitutions are pairs selected from Table 2. 
     
     
         8 . The antibody of  claim 1 , further comprising a detectable label. 
     
     
         9 . A composition comprising an antibody of  claim 1  and a carrier. 
     
     
         10 . The composition of  claim 9 , wherein the carrier is a pharmaceutical carrier. 
     
     
         11 . A complex comprising an antibody of  claim 1  bound to one or more antigens. 
     
     
         12 . An antibody comprising:
 (a) a monovalent unit comprising a light chain-heavy chain pair having specificity to a tumor antigen selected from the group consisting of CD20, CD133 and EGFR, wherein the heavy chain comprises a first human or a humanized IgG1 Fc fragment; and   (b) a single-chain unit comprising a second human or a humanized IgG1 Fc fragment and a fusion peptide comprising a single-chain variable (scFv) having specificity to CD3, wherein the scFv has Formula (I): VH-X-VL wherein X is a linker, and where VL is linked to the second Fc fragment, wherein the single-chain unit does not contain a CH1 domain.