resDNASEQ™ Quantitative CHO DNA Kits

This quantitative PCR (qPCR)-based kit, part of the resDNASEQ™ Quantitative CHO DNA system, enables the detection of sub-picogram amounts of residual DNA from the Chinese hamster ovary (CHO) cell line in under five hours. The system overcomes the limitations of traditional methods by combining high-recovery PrepSEQ™ sample preparation and TaqMan™-based quantitation of residual DNA.

This kit is specifically designed for the Chinese market and manufactured at our Guangzhou site to enable local biopharmaceutical and biotech companies to leverage a highly sensitive, world-class residual DNA quantitation solution.

This kit is available with or without sample preparation reagents in the form of a PrepSEQ Residual DNA Sample Preparation Kit, which is optimized for highly efficient residual DNA recovery from complex mixtures of proteins, buffers, and salts.

Features of the resDNASEQ Quantitative CHO DNA Kit include:

• Real-time quantitative PCR kit for highly sensitive residual CHO DNA quantitation
• Easy to use, results in under five hours
• Specific to CHO DNA, no cross-reactivity with unrelated DNA
• Part of an integrated system that includes sample preparation, TaqMan™ assay and master mix, standard DNA, instrument, and software
• Protocol available for automated sample preparation
• Flexible sample throughput allows you to perform rigorous DNA clearance studies

Real-time PCR for highly sensitive quantitation

The resDNASEQ™ Quantitative CHO DNA Kit provides highly sensitive detection of CHO DNA, allowing the use of small sample volumes to generate accurate results. The broad linear range of TaqMan™ technology allows the testing of samples with variable levels of CHO DNA in the same assay, such as in-process samples with higher amounts of DNA or bulk drug substance with very low amounts. Figure 1 demonstrates the range and sensitivity of the assay. Linearity is demonstrated by analysis of CHO cell standard DNA ranging from 0.3 ng to 3 fg.

Easy to use with results in under five hours

The protocol begins with the extraction of DNA from in-process purification and drug substance samples. qPCR is then performed to compare DNA amounts in the test samples to a standard curve generated with known amounts of purified CHO cell standard DNA. The overall workflow consists of sample preparation, assay setup, and instrument run and data analysis—all of which can be performed in under five hours.

Specific to CHO DNA with no cross-reactivity

The assay detects a hamster-specific region of a multicopy genetic element. This region was selected using extensive bioinformatic analysis of multiple related and unrelated species. Testing of assay performance confirmed that the assay is specific to hamster DNA and is unaffected by the presence of as much as 100 ng of unrelated DNA in a test sample.

Consistent performance even with fragmented DNA

For accurate quantitation of residual CHO DNA, assay results must be unaffected by the size of the DNA molecules present in the test sample. To test the effect of DNA fragment size on assay performance, we fragmented high molecular weight CHO genomic DNA into low molecular weight DNA by sonication. Figure 2 demonstrates that the threshold cycle (Ct) values for the reactions with the sonicated low molecular weight DNA were comparable to those of the undigested high molecular weight DNA. These results demonstrate that consistent performance was obtained with the kit irrespective of DNA molecular weight.