Real-time quantitative PCR kit for highly sensitive residual CHO DNA quantitation
• Easy to use, results in under 5 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

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.

Real-Time PCR for Highly Sensitive Quantitation
The resDNASEQ™ Quantitative CHO DNA System provides highly sensitive detection of CHO DNA, allowing you to use small sample volumes to generate accurate results. The broad linear range of TaqMan™ technology allows you to test 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, Results in Under 5 Hours
First, you extract DNA from your in-process purification and drug substance samples. Then you perform qPCR to compare DNA amounts in your test samples to a standard curve generated with known amounts of purified CHO cell standard DNA. The easy workflow of the resDNASEQ™ Quantitative CHO DNA System consists of sample preparation, assay setup, and instrument run and data analysis—all of which you can perform in under 5 hours.

Specific to CHO DNA, No Cross-Reactivity With Unrelated DNA
The target of the assay is highly specific, so that it only detects a hamster-specific region of a multicopy genetic element. We selected this region 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.