Microscale screening of antibody libraries as maytansinoid antibody-drug conjugates

ABSTRACT

Antibody-drug conjugates (ADCs) are of great interest as targeted cancer therapeutics. Preparation of ADCs for early stage screening is constrained by purification and biochemical analysis techniques that necessitate burdensome quantities of antibody. Here we describe a method, developed for the maytansinoid class of ADCs, enabling parallel conjugation of antibodies in 96-well format. The method utilizes ∼100 µg of antibody per well and requires <5 µg of ADC for characterization. We demonstrate the capabilities of this system using model antibodies. We also provide multiple examples applying this method to early-stage screening of maytansinoid ADCs. The method can greatly increase the throughput with which candidate ADCs can be screened in cell-based assays, and may be more generally applicable to high-throughput preparation and screening of different types of protein conjugates.

KEYWORDS:

• Antibody
• antibody-drug conjugate
• conjugation
• high-throughput
• maytansinoid
• protein chemistry

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Acknowledgments

The authors wish to acknowledge Erin K. Maloney, Laura Bartle, Olga Ab, Ling Dong, and Yulius Setiady for expert assistance with cell assays; and Thomas A. Keating for helpful discussions on the manuscript.