Quantification of residual CHO host cell DNA in biotherapeutics in-process samples using KingFisher Flex system

Fabian vandermeers
Estelle Lara
Arnaud Delobel

Nowadays, biopharmaceuticals as monoclonal antibodies and recombinant proteins represent a very important class of medicines with applications in oncology and immunodeficient diseases.

Most of these recombinant protein therapeutics are produced in mammalian cells. Even though rigorous purification steps are performed, host cell DNA can be found as contaminants in biopharmaceutical products. The presence of such residual DNA in the body may lead to increased oncogenicity and cause adverse immunogenic reactions in patients.

Hence, the demonstration that host cell DNA is removed during the purification of biopharmaceutical products is required to ensure that these impurities are reduced to levels below those guided by regulatory agencies.

Among the methods of detection for residual DNA, quantitative real-time PCR (qPCR) is considered to be the most relevant method due to its high sensitivity, accuracy and precision.

The resDNASEQ kit (ThermoFisher Scientific) is a qPCR-based assay that was designed and developed specifically to enable sensitive and accurate quantification of residual host cell DNA.

This semi-automated equipment is ideal for highthroughput processing, as it can extract 96 samples in less than 2 hours.

In this study, the extraction efficiency and reproducibility of the PrepSEQ and resDNASEQ kits were evaluated using real-time PCR. CHO cell DNA standard was spiked into different sample matrices at various concentrations. Samples were extracted either manually or in a 96-well plate format with the semi-automatic KingFisher Flex equipment. Automatic extraction showed several advantages compared with the manual method.