Antibody-active agent conjugates and methods of use

An antibody-active agent conjugate comprising:

• (a) a full-length antibody comprising two immunoglobulin heavy chains and two immunoglobulin light chains, wherein the antibody recognizes and specifically binds to a target through at least one antigen recognition site;
• (b) at least one amino acid motif having an amino acid sequence CAAX, wherein C represents cysteine, A represents an aliphatic amino acid, and X represents an amino acid that determines a substrate specificity of the isoprenoid transferase, directly or indirectly linked to a carboxy terminus of a heavy chain or light chain of the antibody, wherein the amino acid motif is recognizable by an isoprenoid transferase;
• (c) an isosubstrate directly linked to a cysteine moiety of the at least one amino acid motif, wherein the isosubstrate contains at least one isoprenoid unit and is recognizable by the isoprenoid transferase;
• and
• (d) at least one active agent, wherein the active agent is a drug, and the drug is directly or indirectly linked to the isosubstrate.