In a recent SelectScience webinar Dr Ning Tang, Biopharma Discovery Segment Marketing Manager at Agilent Technologies, discussed challenges in characterizing Antibody-Drug Conjugates and how LC/MS technology can be used to overcome them. She also introduces new technology being used for rapid Drug-to-Antibody Ratio (DAR) calculations.
In this article read the highlights of the Q&A session from Dr Tang’s presentation, or watch it again on demand here.
Q: What is the loading capacity of the AssayMAP protein A cartridge?
A: The AssayMAP protein A and protein G cartridges have quantitative binding capacity (less than 10% of the load in the flow through) of approximately 100 microgram of antibody. The capacity for other cartridge depends on the resin type. A complete description of the capacity of all the AssayMAP cartridge types can be found in the AssayMAP Cartridge Selection Guide.
Q: I typically deglycosylate my ADCs after I purify them, can your automated platform do this?
A: Yes, absolutely, the AssayMAP platform allows you to automate the multiple steps required for executing complex sample preparation workflows. The AssayMAP platform comes with easy-to-use applications for doing affinity purification, glycan analysis, digestion, peptide clean-up, phosphopeptide enrichment, and peptide fractionation. You can combine these applications in any order allowing you to address a vast array of complex sample preparation workflows.
Q: You showed an example of purifying an ADC out of serum using the antigen as the capture ligand, have you tried a similar experiment where you immobilize a capture antibody targeted against the ADC?
A: Yes, you can purify the ADC out of serum using a biotinylate antigen as we showed in the webinar. We have also immobilized a biotinylated antibody against ADC to purify the ADC out of serum. This works if the capture antibody has high affinity and specificity.
Q: Is the MassHunter ADC DAR calculator available, will it be included in BioConfirm software?
A: Yes, the DAR calculator is available now, it is one of the options of the MassHunter BioConfirm software so you just have to specify that you want to have the DAR calculator on top of the BioConfirm software package.
Q: Can the AssayMAP cartridges be reused?
A: We recommend AssayMAP cartridges be considered single use. AssayMAP cartridges are effectively 5 µL packed bed columns so if you want to explore re-use treat them like columns by using stringent washes and proper storage solutions. However, we do recommend single use for these tips to ensure the best performance.
Q: In the positive displacement pipetting step is there a problem of leftover samples that might be in the next run?
A: Any concerns about carryover between runs can be addressed using the Syringe Wash utility included in the AssayMAP software package. This utility can be used to wash the syringes with the appropriate wash solution to ensure there is no run-to-run carryover.