Application of a Novel Aptamer Beacon for Rapid Detection of IgG1 Antibody Drugs

Antibody drugs have been widely used to treat many diseases and are the fastest-growing drug class. IgG1 is the most common type of antibody because of its good serum stability; however, effective methods for the rapid detection of IgG1-type antibodies are lacking. In this study, we designed two aptamer molecules derived from the reported aptamer probe that has been proven to bind to the Fc fragment of the IgG1 antibody. The results showed that Fc-1S could specifically bind to the human IgG1 Fc proteins. In addition, we modified the structure of Fc-1S and constructed three aptamer molecular beacons that could quantitatively detect IgG1-type antibodies within a short time. Furthermore, we unveiled that the Fc-1S37R beacon has the highest sensitivity for IgG1-type antibodies with a detection limit of 48.82813 ng/mL and can accurately detect serum antibody concentrations in vivo with consistent results to ELISA. Therefore, Fc-1S37R is an efficient method for the production monitoring and quality control of IgG1-type antibodies to enable the large-scale production and application of antibody drugs.