Purpose: Accurate quantification of soluble glypican-3 in clinical samples using immunoassays is challenging due to the lack of appropriate antibody reagents to provide a full spectrum measurement of all potential soluble glypican-3 fragments in vivo. Glypican-3 SOMAmer (Slow Off-Rate Modified Aptamer) is a novel reagent which binds, with high affinity, to a far distinct epitope of glypican-3 when compared to all available antibody reagents generated in house.
Methods: This poster describes an integrated analytical approach to rational selection of key reagents based on molecular characterization by epitope mapping, with the focus on our work using a SOMAmer as a new reagent to address development challenges with traditional antibody reagents for the soluble glypican-3 immunoassay. A qualified SOMAmer-based assay was developed for soluble glypican-3 quantification in hepatocellular carcinoma (HCC) patient samples.
Results: The assay demonstrated good sensitivity, accuracy, and precision. Data correlated with those obtained using the traditional antibody-based assay (Pearson’s r = 0.955) were used to confirm the clinically relevant soluble glypican-3 forms in vivo. This result was reinforced by a liquid chromatography tandem mass spectrometry (LC-MS/MS) assay quantifying signature peptides generated from trypsin digestion.
Conclusion: The work presented here offers an integrated strategy for qualifying aptamers as an alternative affinity platform for immunoassay reagents that can enable speedy assay development especially when traditional antibody reagents cannot meet assay requirements.
Camelia Chiriac– Research Scientist, Bristol-Myers Squibb Company, Princeton
Richard Huang– Bristol-Myers Squibb Company
John Mehl– Bristol-Myers Squibb Company
Guodong Chen– Bristol-Myers Squibb Company
Adrienne Tymiak– n/a
Peter Sabbatini– Bristol-Myers Squibb Company
Renuka Pillutla– Executive Director, Bristol-Myers Squibb Company
Yan Zhang– Director, Analytical and Bioanalytical Operations, Bristol-Myers Squibb Company, Princeton, New Jersey