Human Serum Albumin Domain I Fusion Protein for Antibody Conjugation

• Published in: Bioconjugate chemistry Vol. 27; no. 10; pp. 2271 - 2275
• Main Authors: Patterson, James T, Wilson, Henry D, Asano, Shigehiro, Nilchan, Napon, Fuller, Roberta P, Roush, William R, Rader, Christoph, Barbas, Carlos F
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 19.10.2016
• Subjects: Antibodies - chemistry; Breast Neoplasms - metabolism; Cell Line, Tumor; Female; Flow Cytometry; Humans; Immunoconjugates - blood; Immunoconjugates - chemistry; Immunoconjugates - metabolism; Lysine - chemistry; Molecules; Peptides; Plasma; Protein Domains; Protein Engineering - methods; Proteins; Receptor, ErbB-2 - metabolism; Recombinant Fusion Proteins - blood; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Rhodamines - chemistry; Serum Albumin - chemistry; Trastuzumab - chemistry
• ISSN: 1043-1802; 1520-4812
• DOI: 10.1021/acs.bioconjchem.6b00432

Bioorthogonal labeling of antibodies enables the conjugation of compounds, such as small molecules or peptides, which expand targeting capacity or enhance cytotoxicity. Taking advantage of a cyclohexene sulfonamide compound that site-selectively labels Lys64 in human serum albumin (HSA), we demonstrate that domain I of HSA can be used as a fusion protein for the preparation of antibody conjugates. Trastuzumab fusions were expressed at the N-terminus of the light chain or the C-terminus of the heavy chain enabling conjugation to small molecules. Moreover, these conjugates retained HER2 binding and proved to be highly stable in human plasma. Antibody conjugation via HSA domain I fusion should therefore have broad utility for making serum-stable antibody conjugates, particularly for antibody–drug conjugates.