Antibodies comprising site-specific non-natural amino acid residues, methods of their preparation and methods of their use

A method of detecting an antigen, comprising:

• contacting a sample comprising the antigen with an antibody conjugate or a pharmaceutical composition comprising the antibody conjugate, wherein the antibody conjugate comprises an isolated antibody of the IgG1 class comprising a heavy chain and a light chain, wherein the antibody conjugate binds to the antigen, and wherein:
• the heavy chain comprises at least one non-natural amino acid residue at a specific site selected from the group consisting of heavy chain residues 19, 25, 40, 52, and 70 according to the Kabat numbering scheme and heavy chain residues 119, 121, 180, 190, 222, 241, and 404 according to the EU index of Kabat;
• or
• the light chain comprises a non-natural amino acid residue at a specific site selected from the group consisting of the light chain residues 7, 22, and 152 according to the Kabat numbering scheme;
• or a combination thereof;
• or an aglycosylated variant thereof;
• wherein each non-natural amino acid residue is independently selected from the group consisting of ortho-substituted tyrosine, meta-substituted tyrosine, para-substituted phenylalanine, ortho-substituted phenylalanine, and meta-substituted phenylalanine;
• wherein at least one of the non-natural amino acids is linked to a payload capable of being detected;
• and
• detecting a complex formed between the antibody and the antigen.