Bispecific intracellular delivery vehicles

Abstract

A composition for delivering an agent to a cell, comprising a bispecific affinity reagent and a pH-responsive, membrane destabilizing polymer. The bispecific affinity reagent may include a first affinity reagent covalently linked to a second affinity reagent, wherein the first affinity reagent binds to a molecule on the surface of a cell, and the second affinity reagent binds to an intracellular target.

1 - 47 . (canceled) 
     
     
         48 . A composition comprising:
 a bispecific affinity reagent comprising a first affinity reagent covalently linked to a second affinity reagent, wherein the first affinity reagent binds to a molecule on the surface of a cell and the second affinity reagent binds to an intracellular target, and wherein the bispecific affinity reagent is a bispecific antibody; and   a pH-responsive, membrane destabilizing polymer.   
     
     
         49 . The composition of  claim 48 , wherein the bispecific antibody is selected from the group consisting of a tandem scFv, a heterodimeric scFv, a diabody, a minibody, a quadroma, and an scFv recombinantly fused to a whole antibody. 
     
     
         50 . The composition of  claim 48 , wherein the bispecific antibody is a humanized antibody. 
     
     
         51 . The composition of  claim 48 , wherein the first and second affinity reagents are present in a single polypeptide chain. 
     
     
         52 . The composition of  claim 48 , wherein the bispecific affinity reagent is produced in a host cell as two separately encoded polypeptide chains that are linked by disulfide bonds. 
     
     
         53 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer comprises a plurality of pendant linking groups, and wherein the bispecific affinity reagent is linked to the polymer via the plurality of pendant linking groups. 
     
     
         54 . The composition of  claim 48 , wherein the bispecific affinity reagent is cleavably linked to the polymer through a pH-sensitive bond. 
     
     
         55 . The composition of  claim 54 , wherein the pH-sensitive bond is a hydrazone or acetal. 
     
     
         56 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer is a copolymer. 
     
     
         57 . The composition of  claim 56 , wherein the pH-responsive, membrane destabilizing polymer is a block copolymer. 
     
     
         58 . The composition of  claim 57 , wherein the pH-responsive, membrane destabilizing polymer is a diblock copolymer. 
     
     
         59 . The composition of  claim 57 , wherein the block copolymer comprises a hydrophobic, membrane destabilizing block and a hydrophilic block. 
     
     
         60 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer has a polydispersity index (PDI) of less than 2.0. 
     
     
         61 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer is produced using controlled radical polymerization. 
     
     
         62 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer comprises monomeric residues derived from polymerization of ethylenically unsaturated monomers. 
     
     
         63 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer comprises monomeric residues derived from polymerization of a (C 2 -C 8 ) alkylacrylic acid. 
     
     
         64 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer comprises monomeric residues derived from polymerization of a (C 2 -C 8 ) alkyl-ethacrylate, a (C 2 -C 8 ) alkyl-methacrylate, or a (C 2 -C 8 ) alkyl-acrylate. 
     
     
         65 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer comprises monomeric residues derived from polymerization of N,N-di(C 1 -C 6 )alkyl-amino(C 1 -C 6 )alkyl-ethacrylate, N,N-di(C 1 -C 6 )alkyl-amino(C 1 -C 6 )alkyl-methacrylate, or N,N-di(C 1 -C 6 )alkyl-amino(C 1 -C 6 )alkyl-acrylate. 
     
     
         66 . The composition of  claim 48 , wherein the pH-responsive, membrane destabilizing polymer comprises a random copolymer chain having monomeric residues derived from polymerization of propyl acrylic acid, N,N-dimethylaminoethylmethacrylate, and butyl methacrylate. 
     
     
         67 . The composition of  claim 66 , wherein the pH-responsive, membrane destabilizing polymer is a block copolymer comprising said random copolymer chain as a membrane disrupting polymer block, and further comprising one or more additional blocks.