Sulfo-tag and Biotin are protein tags frequently used for labeling antigen proteins in electrochemiluminescence (ECL) assay platforms. Biotin-conjugated material may serve as either capture or detection reagents, whereas Sulfo-tag-conjugated molecules function as detectors in immunoassays. During the application of ECL immunoassays, we encountered systematic issues with conjugate aggregation, resulting in elevated ECL values in controls, particularly negative controls, which adversely affected the progress of new drug development. This study aims to investigate the cause of the observed increase in ECL values of negative controls in anti-drug antibody assays. The results indicated that warming the conjugates at 37C for 1.5 hours or cooling the conjugates at 4C overnight prior to preparing the working conjugate solution reduced the elevated NC signals, meeting the NC acceptance criteria for the assays. This finding suggests potential aggregation of Biotin and Sulfo-tag labelled proteins after long-term frozen storage, impacting the performance of ECL immunoassays.
Learning Objectives:
Upon completion, participant will be able to learn how to recognize the aggregation of Sulfo-tag and biotinylated conjugates
Upon completion, participant will be able to know which conjugate, Sulfo-tag or biotinylated conjugates or both contribute to aggregation
Upon completion, participant will be able to learn how to solve this issue and know some potential prevention methods against aggregation of conjugates
