Methods of preparing antibody-active agent conjugates

Abstract

The invention provides methods for preparing an antibody-active agent conjugate. The conjugate comprises an antibody, a cysteine residue of an amino acid motif that can be recognized by an isoprenoid transferase located at or after the carboxy-terminus of the antibody, an isoprenoid unit operably linked to the cysteine residue, and an active agent. The invention also provides a composition comprising the antibody-active agent conjugate prepared by the methods.

1 . A method for preparing an antibody-active agent conjugate, wherein the conjugate comprises an antibody, a cysteine residue of an amino acid motif that can be recognized by an isoprenoid transferase located at or after the carboxy-terminus of the antibody, an isoprenoid unit operably linked to the cysteine residue, and an active agent,
 the method comprising:   (a) obtaining an antibody that is attached to an amino acid motif that can be recognized by an isoprenoid transferase;   (b) obtaining a functionalized antibody by enzymatically prenylating, in the presence of the isoprenoid transferase, the obtained antibody with at least one isosubstrate of the isoprenoid transferase, wherein the isosubstrate contains at least one isoprenoid unit and a first functional group (FG1) attached thereto;   (c) obtaining a functionalized active agent which is an active agent attached to a second functional group (FG2); and   (d) reacting the FG1 of the functionalized antibody with the FG2 of the functionalized active agent to yield the antibody-active agent conjugate,   wherein the conjugate comprises an antibody, a cysteine residue of an amino acid motif that can be recognized by an isoprenoid transferase located at or after the carboxy-terminus of the antibody, an isoprenoid unit operably linked to the cysteine residue, and an active agent.   
     
     
         2 . An antibody-active agent conjugate prepared by the method of  claim 1 . 
     
     
         3 . A composition comprising the antibody-active agent conjugate of  claim 2 . 
     
     
         4 . A method for preparing an antibody-active agent conjugate, wherein the conjugate comprises an antibody, a cysteine residue of an amino acid motif that can be recognized by an isoprenoid transferase located at or after the carboxy-terminus of the antibody, an isoprenoid unit operably linked to the cysteine residue, and an active agent,
 the method comprising:   (a) obtaining an antibody that is attached to an amino acid motif that can be recognized by an isoprenoid transferase;   (b) obtaining a functionalized active agent by covalently attaching to an active agent at least one isosubstrate of the isoprenoid transferase, wherein the isosubstrate contains at least one isoprenoid unit and a functional group attached thereto; and   (c) enzymatically prenylating, in the presence of the isoprenoid transferase, the obtained antibody with the functionalized active agent to yield the antibody-active agent conjugate,   
     
     
         5 . An antibody-active agent conjugate prepared by the method of  claim 4 . 
     
     
         6 . A composition comprising the antibody-active agent conjugate of  claim 5 .