Rituxan ADCC & CDC Assays

BioOutsource has the experience, expertize and capabilities to provide complete ADCC and CDC testing solutions for Rituxan using our off-the-shelf methods for both Rituxan CDC and ADCC. We offer a range of Fc Receptor binding assays to complement our functional ADCC assay, and C1q binding assays to complement our functional CDC assay.

The Rituxan CDC and ADCC bioassays measure the combined activity of the Fab binding and effector functions of Rituxan, mediated through C1q binding (CDC) or the Fc-Gamma Receptor IIIa (FcRIIIa) (ADCC). BioOutsource are industry experts in the development, optimization and qualification/validation of bioassays and have applied this expertise to Rituxan (rituximab) to offer ADCC and CDC assays to our customers. We have performed our existing methodology, adapted to incorporate the customer’s reference standard of choice, to support clone selection, comparability and biosimilarity activities. Where required, assay qualification and/or validation can be achieved using customer’s material.

The principle of both Rituxan (rituximab) ADCC and CDC assays is that the relevant target cell line, typically Raji, Daudi or Ramos cells, expressing the CD20 protein are prepared in cell plates using a procedure design to optimize receptor expression. A dilution series of Rituxan is then prepared, added to the plate and allowed to bind to the target cells for period of time. Engineered cells stably expressing the FcgRIIIa receptor (Rituxan ADCC bioassay) or complement (Rituxan CDC bioassay) is then added to the target cells; this will bind to Rituxan which is in turn bound to the CD20 protein on the cell surface, resulting in target cell lysis (CDC), or a luminescent signal (ADCC). The assays are performed with appropriate assay controls, utilizing a non-radioactive assay endpoint. Sample results can be reported as a per cent of total cell death or as a relative potency measurement against the Reference Standard.

ADCC assays are well known for day to day variability and BioOutsource have implemented a number of different strategies to control this variation and implement standardized cell culture regimes. Our standard CDC assay methodologies have been optimized using a specific complement source.

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