The Use of ForteBio’s Octet at Biogen Idec

Presented at PEGS 2009

Brian Miller, Sr. Scientist, Antibody Engineering,
Biogen Idec.

This article is a summary of the presentation made at the PEGS conference in Boston earlier this year.

There are currently several Octet (QK and RED) systems in use at Biogen Idec, both in Cambridge and in San Diego. The main functions of the Octet systems at Biogen Idec are: protein quantitation, off-rate screening of crude samples, monoclonal antibody cross-blocking, epitope scanning and affinity ranking with purified material.

For protein quantitation applications such as clone/host/media ranking, following cultures over time and determining titer for downstream purification, the Octet system has several advantages. The instrument offers ease of use, fast quantitation (8 samples in about 3 minutes) without the need for sample preparation or dilution and customized quantitation using Streptavidin biosensors and biotinylated ligand. A single read is typically enough for accurate quantitation and pre-generated standard curves can be used for a majority of applications.

For off-rate screening for library triage, while protein aggregation may provide odd-looking binding curves, crude samples that are unsuitable for Biacore analysis due to media composition and unfilterable cell debris can be analyzed readily on the Octet. The Octet is relatively insensitive to components such as detergent, non-specific proteins and nucleic acids in crude samples. Also, changes in refractive index between sample and buffers have no effect on the signal. The throughput of the Octet allows us to rapidly assess the off-rate of 50–100 samples per day as a rapid means of triaging mutant proteins (Figure 1).

The Octet is used to rapidly determine which monoclonal antibodies cross-block each other by performing sandwich assays on either the biosensor surface or by competition in solution (Figure 2). Large numbers of epitope scanning mutations were analyzed kinetically for their effects on monoclonal antibody binding without the need for purification of each mutant protein.

The Octet also provided accurate affinity constant values for a variety of antibodies and antibody fragments with single and multiple valencies.

In summary, the Octet systems have rapidly become an integral part of research workflows in multiple groups at Biogen Idec. Some advantages in addition to those mentioned above, include rapid assay development, direct transferability of regeneration conditions developed on a Biacore to the Octet, and minimal operational expenses.

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