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

Fabian vandermeers
Estelle Lara
Arnaud Delobel

The presence of residual host cell DNA in biopharmaceutical products can induce severe side effects for patients. The demonstration that host cell DNA is removed during the purification of biopharmaceutical products is required by regulatory agencies; hence, the need for sensitive, accurate and precise methods. Real-time PCR shows all of these characteristics, but the sample preparation is often time-consuming and can induce variability.

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. First, it offers consistent highthroughput extraction and purification of DNA (up to 96 samples in less than 2 hours) without an extensive intervention of the analyst. In addition, the KingFisher Flex extraction offers better accuracy, precision and a wider quantification range, especially for low DNA concentrations. Furthermore, it strongly reduces the risk of errors and contaminations. Finally, the KingFisher Flex can be used for other applications such as extraction of RNA, proteins or cells.

In conclusion, by using the PrepSEQ kit coupled with the KingFisher Flex system and the resDNASEQ kit, we have demonstrated quantitative CHO residual DNA recovery from a variety of complex sample matrices.