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ForteBio Interactions Newsletter Biosensor photo

October 2009    VOLUME 2    ISSUE 3


The Label-Free Revolution Continues!

Residual Protein A Detection Assay

John Proctor, Ph.D., Product Manager

Detection of residual Protein A in product purified from a Protein A, or similar purification column, is a critical quality control step in antibody therapeutic development and production. During the IgG purification process, Protein A can leach off the purification column matrix and co-elute with the IgG. This contaminant can cause adverse reactions in patients, so it must be detected and minimized.

ForteBio is pleased to announce the first label-free Dip and Read™ Residual Protein A Detection Kit for use on the Octet platform. This new kit provides the sensitivity and accuracy needed to perform quantitation of contaminating Protein A in IgG-containing samples with results in two hours.

ForteBio’s development team has optimized sample pretreatment to overcome any interference from IgGs in the sample, while delivering a 100 pg/mL lower limit of detection. This easy-to-use kit provides unparalleled hands-off time when used in conjunction with the new Sidekick™ station (see article, page 3), which allows the assay to be run in two hours from start to finish, with no washing! And, the simplicity of the Octet system also allows this assay to be run completely label-free.

The Dip and Read Residual Protein A Detection Kit contains the biosensors and all the reagents required to quantitate Protein A from column fractions. The biosensor supplied with the kit comes pre-immobilized with an antibody that recognizes native Protein A (S. aureus), recombinant Protein A (E. coli), and engineered Protein A biosimilars such as GE Healthcare’s MabSelect SuRe™.

Once the sample is bound, the biosensors are then immersed briefly into an unlabeled secondary detection antibody to form a sandwich complex. Formation of the complex is all that is required for the Octet platform’s proprietary BLI technology to detect the mass of the sample on the biosensor. From this point, data from both standards and samples can be immediately analyzed in just three mouse-clicks to determine the concentration of residual Protein A in each sample.

Dip and Read Residual Protein A Detection Kit Contents (P/N 18-5075):

  • 1 tray (96) Residual Protein A biosensors*
  • 1 bottle Sample Denaturing Buffer
  • 1 bottle Neutralization Buffer
  • 1 bottle Sample Diluent
  • 1 bottle Sample Diluent+PEG
  • Protein A Detection Reagent
  • Recombinant Protein A Calibrator

* Store biosensors in the provided re-sealable bag in a dry place at room temperature away from direct sunlight. Dispose of biosensors as sharps. Upon receipt, biosensors are stable for 6 months.

Ensure all reagents are equilibrated to room temperature prior to running the assay

For more information, or to order your Dip and Read Residual Protein A Detection Kit today, visit