Ruthenium-labeled antibodies are commonly used detection reagents in bioanalysis assays and must be characterized to ensure quality. The aim of this work was to develop a method to determine the concentration and incorporation ratio (the degree of labeling [DOL]) of ruthenium-labeled antibodies by UV/VIS spectroscopy. Free SULFO-TAG compound was scanned using UV/VIS and showed an absorbance peak at 292 nm. In contrast, antibodies demonstrate UV absorbance at 280 nm. After experimentally determining the extinction coefficients at 280 and 292 nm of free ruthenium and antibody, we generated a formula based on the Beer-Lambert law that calculates both concentration and DOL of these ruthenium-labeled antibodies. The concentration and DOL values determined by our method were comparable to those determined from bicinchoninic acid and LC/MS for the same reagents. This method creates a faster and more accessible reagent characterization process that uses far less reagent than the more traditional alternatives.
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http://dx.doi.org/10.4155/bio-2021-0197 | DOI Listing |
J Pharmacol Toxicol Methods
December 2023
Global Drug Metabolism and Pharmacokinetics, Eisai Co., Ltd., Tokodai 5-1-3, Tsukuba, Ibaraki 300-2635, Japan; Laboratory of Genomics-based Drug Discovery, Faculty of Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8575, Japan. Electronic address:
E6011, a humanized anti-fractalkine monoclonal antibody, is under development for the treatment of various inflammatory diseases, such as rheumatoid arthritis. Therapeutic antibodies may induce production of anti-drug antibodies (ADA) that may deteriorate efficacy and/or enhance immunogenic reaction. It is important to have an ADA assay to understand the characteristics of biotherapeutics under development.
View Article and Find Full Text PDFJ Pharmacol Toxicol Methods
January 2023
Global Drug Metabolism and Pharmacokinetics, Eisai Co., Ltd., Tokodai 5-1-3, Tsukuba-shi, Ibaraki 300-2635, Japan; Laboratory of Genomics-Based Drug Discovery, Faculty of Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8575, Japan. Electronic address:
Denileukin Diftitox (DD), comprising fragments of diphtheria toxin (DT) and interleukin-2 (IL2), was developed for the treatment of lymphoma and has been approved for marketing in Japan. Toxicological evaluation including pharmacokinetics and immunogenicity in preclinical animals is important for drug development and thus the assays of DD and anti-drug antibody (ADA) were developed by electrochemiluminescence (ECL) detection. For the DD assay, ruthenium-labeled anti-DT Ab and biotinylated anti-IL2 Ab were mixed with serum samples and the mixture was captured by streptavidin-coated wells for ECL detection.
View Article and Find Full Text PDFJ Immunol Methods
January 2023
Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA.
Adeno-associated virus (AAV) based gene therapies are gaining significant momentum as a novel therapeutic modality. However, a yet unsolved concern for using AAV as a vector is the high potential to elicit humoral and cellular responses, which are often exacerbated by pre-existing immunity due to exposure to wild type AAV. Therefore, characterization of pre-existing and treatment emergent anti-AAV antibodies is of great importance to the development of AAV based gene therapies.
View Article and Find Full Text PDFBioanalysis
January 2022
Bioanalysis, Immunogenicity & Biomarkers, GlaxoSmithKline R&D, 1250 S Collegeville Road, Collegeville, PA 19426, USA.
Ruthenium-labeled antibodies are commonly used detection reagents in bioanalysis assays and must be characterized to ensure quality. The aim of this work was to develop a method to determine the concentration and incorporation ratio (the degree of labeling [DOL]) of ruthenium-labeled antibodies by UV/VIS spectroscopy. Free SULFO-TAG compound was scanned using UV/VIS and showed an absorbance peak at 292 nm.
View Article and Find Full Text PDFJ Clin Lab Anal
January 2019
Drug Metabolism and Pharmacokinetics, Biopharmaceutical Assessments Core Function Unit, Eisai Co., Ltd., Ibaraki, Japan.
Background: E6011, a humanized antifractalkine monoclonal antibody, is under development for the treatment of various inflammatory diseases, such as rheumatoid arthritis. A reproducible assay method has been developed for the determination of E6011 in monkey and human serum by electrochemiluminescence (ECL) assay.
Methods: E6011 in serum was captured by fractalkine and detected by ruthenium-labeled rabbit anti-E6011 Fab polyclonal antibodies for ECL detection.
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