bioprocess monitoring kits are being developed to monitor the glycoprofile during bioreactor production run.
GlycoSenseTM Sialic Acid and Galactose Monitoring Kit
More than two thirds of therapeutic biologics and greater than 80% of biosimiliars currently under development are glycosylated recombinant proteins and thus require new tools for glycosylation analysis during bioprocess monitoring. GlycoSenseTM applications include Quality Assurance for bioprocess development and bioprocessing of therapeutic biologics that are glycosylated. Specifically, GlycoSenseTM bioprocess monitoring kits will enable assessing the general features of the glycosylation of a glycoprotein when comparing material produced from different batches or with different cell lines in a near real-time manner during bioreactor production runs. Furthermore, this product may also be used for comparing the glycoprofile of a biosimilar to the reference product as part of determining bioequivalency. Glycosylation variations routinely occur, for example when a new cell-type is employed for expression, and regularly arise from minor differences in growth media. Similarly, variations in viral coat protein glycosylation result from passaging in different cell lines. This is pertinent to vaccine production, and can be readily monitored with the GlycoSenseTM technology.
Key features of the GlycoSenseTM bioprocess monitoring method are that it uses common laboratory equipment (a bench-top flow cytometer), does not require specialist training, is rapid, and is statistically reliable. Although it does not provide a detailed tabulation of individual glycoforms, it provides a reproducible measure (called a “glycoprint”) of the overall state of critical features of the glycosylation. Thus the GlycoSenseTM method offers the potential to shift some aspects of glycoprofiling away from dedicated specialist analytical cores, to direct use within the research laboratory, enabling crucial information to be obtained in a routine and timely manner. Illustrated below is the approach with reference to characterizing features associated with N-glycosylation, but the technique is equally applicable to O-glycosylation. Eukaryotic N-glycans share a common glycan core, and differ in the degree to which they have been processed by organismal enzymes. This processing is reflected in differences in their terminal capping, such as by N-acetylneuraminic acid (Neu5Ac, sialic acid), galactose (Gal), N-acetylglucosamine (GlcNAc), mannose (Man), and fucose (Fuc) (Figure 1).
Figure 1. The five most abundant glycoforms of glycoprotein Robo1-GFP (GFP-tagged Roundabout homolog and a hypothetical “glycoprint” illustrated for five specific glycosylation features. Note: a single glycoform could bind to multiple GlycoSense TM reagents, such as G1F (upper right) binding to three specific elements.