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• ViewdPCR Validation Standards Minerva Biolabs
• ViewMiQuant® Residual DNA dPCR HEK-293 Minerva Biolabs

Testing of Residual Host Cell DNA: Importance in Quality Management of Biologicals

Residual host cell DNA testing is an important part of quality control in the manufacturing of biologics. It helps manufacturers monitor process-related impurities, support batch release and demonstrate that residual DNA from the production cell system is controlled at an acceptable level

1. Background: Why residual host cell DNA testing is critical for biopharmaceuticals

Residual DNA arises during the production of biopharmaceuticals when animal, bacterial, or human host cells are used to produce recombinant proteins, monoclonal antibodies, or vaccines. In these manufacturing processes, host cells are typically lysed to extract the desired therapeutic proteins. Despite extensive purification steps, small amounts of host cell DNA may remain in the final product. This residual DNA can be considered a contamination that may compromise both product quality and patient safety.

2. Why is residual DNA a problem?

Residual DNA in biologics presents various risks:

3. Common host cell systems in biopharmaceutical manufacturing

The host cell system used during manufacturing determines which residual DNA assay is required.

Different biological products are manufactured using different host cell systems. The analytical method used for residual DNA testing should therefore match the production system.

CHO cells

Chinese Hamster Ovary cells, commonly known as CHO cells, are among the most widely used mammalian cell lines in biopharmaceutical manufacturing. They are frequently used for recombinant proteins, monoclonal antibodies, and other complex biologics. Because CHO-based production is so common, CHO residual DNA testing is an important part of quality control for many biopharmaceutical processes.

E. coli

E. coli is a bacterial expression system widely used for the production of recombinant proteins and other biological products. Bacterial production systems can be efficient and well established, but they require specific testing strategies for residual E. coli DNA in the final product or relevant process samples.

HEK-293 cells

HEK-293 cells are human-derived cells commonly used in biopharmaceutical research and production, especially in applications involving viral vectors, vaccines, proteins, and cell and gene therapy-related workflows. For HEK-293-based processes, sensitive and specific detection of residual HEK-293 DNA is required.

4. Regulatory requirements for residual host cell DNA testing: guidelines and limits

Major global regulatory authorities, such as the WHO, FDA, and the European Pharmacopoeia, have established strict limits on the amount of residual DNA in biologics to ensure patient safety.

These limits are considered safe and are intended to minimize the potential risks associated with residual DNA.

5. Methods for detecting and quantification of residual host cell DNA

qPCR

Quantitative PCR is widely used for residual DNA testing. It is sensitive and specific, but typically requires a standard curve for quantification. qPCR remains a common method in many established quality control workflows.

dPCR

Digital PCR enables absolute quantification of DNA molecules without the need for a standard curve. This makes dPCR particularly useful for residual DNA testing, especially when precise quantification of low DNA concentrations is required

Digital PCR enables absolute quantification of DNA molecules without the need for a standard curve. This makes dPCR particularly useful for residual DNA testing, especially when precise quantification of low DNA concentrations is required.

Other methods

Other approaches, such as DNA probe hybridization, fluorescence staining, or immunoassay-based methods, may be used in specific contexts. However, molecular methods such as qPCR and dPCR are commonly preferred when high sensitivity, specificity, and quantitative results are required.

6. Importance of fast and accurate testing

Residual host cell DNA can be present at very low levels and may be highly fragmented due to purification, nuclease treatment, or other process conditions. A robust residual DNA assay should therefore be able to detect degraded DNA reliably and provide quantitative results that support decision-making in quality control.

Fast and accurate testing can help manufacturers:

Digital PCR can support these needs by enabling absolute quantification and precise detection of residual host cell DNA in relevant sample matrices

7. MiQuant® Residual DNA - dPCR assays for CHO, E. coli and HEK-293

To support residual host cell DNA testing in different production systems, Minerva Biolabs offers MiQuant® Residual DNA - dPCR assays for CHO, E. coli and HEK-293. The assays are designed for the quantitative detection of residual host cell DNA in biological and pharmaceutical matrices and support direct sample testing where matrix compatibility is given

Key features of the MiQuant® Residual DNA - dPCR assays:

	MiQuant® Residual DNA CHO - dPCR	MiQuant® Residual DNA E. coli – dPCR	MiQuant® Residual DNA HEK-293 - dPCR
Application	CHO-based biologics, e.g. recombinant proteins and antibodies	Bacterial expression systems, proteins and vaccines	HEK-293-based products, e.g. viral vectors, proteins and vaccines
Limit of detection	0.04 fg/µl	0.13 fg/µl	1.7 fg/µl
Limit of quantification	≥0.33 fg/µl	1 fg/µl	≥5 fg/µl
Specificity	No cross-reactivity detected