Monitoring Protein Titer and Glycosylation Simultaneously
Cell line development typically includes the screening of thousands of clones in an effort to find the few that are stable, grow as expected, and produce high product yields. The time it takes from engineering an optimal cell line to the production of the target biologic can be prohibitive and may differ from molecule to molecule. While expression level analysis like titer screening is carried out early, other critical quality attributes (CQAs) such as glycan characterization are often assessed only later in the development process due to a lack of appropriate and high-throughput analytical techniques that can be used to perform quick screens.
Commonly used methods for antibody quantitation require either specialized instrumentation and skilled personnel (HPLC) or are time-consuming (ELISA). In contrast, the Octet® BLI platform uses Bio-Layer Interferometry (BLI) to detect real-time binding of molecules as a means of quantification or for kinetic analysis. This label-free technology essentially eliminates any sample preparation beyond an optional dilution step. BLI measures only what’s captured on biosensor chemistries, making it specific when measuring in complex matrices such as crude supernatants. High-throughput Octet® models can process up to 96 samples simultaneously.
The Sartorius Octet® Gly S and GlyM Kits are designed to provide cell line development scientists and scientists in upstream bioprocessing with ready to use kits for the rapid screening of % mannose content or relative sialic acid levels of purified and cell harvest antibody samples. The results correlate well with HPLC and mass spec techniques in rank ordering of samples with the added advantage that the assays used early on in the development process do not require sample purification or enzymatic digestion prior to sample analysis.
In combination with e.g. titer determination using the same sample, up to 1,000 clones can be screened in just under 10 hours. When combined with the high-throughput features of Octet® instruments and the flexibility of sample analysis using a variety of off-the shelf biosensors; including for titer determination, specificity to target antigen binding and off-rate analysis (all from the same sample set); it is an added tool for the assessment of critical quality attributes (CQAs) that should facilitate the early selection of optimal clones during cell line development preventing late failures moving higher quality candidates downstream.
