GeticoSEQ 293 DNA Residue Quantitative Kit

Product Overview

The GeticoSEQ 293 DNA Residue Quantitative Kit is a high-performance molecular detection reagent developed by Shanghai Getico Scientific, specifically designed for the accurate and sensitive quantification of residual 293 cell DNA in biopharmaceutical products (such as monoclonal antibodies, recombinant proteins, vaccines) and biological samples. As 293 cells are widely used as host cells in biopharmaceutical production, residual 293 DNA in final products may pose potential safety risks (e.g., oncogenicity, immunogenicity) to patients. This kit adheres to international guidelines (including ICH Q5A, FDA recommendations) and uses real-time quantitative PCR (qPCR) technology to provide reliable, rapid, and reproducible detection results, helping biopharmaceutical enterprises and research institutions meet strict product quality control (QC) requirements during the development, production, and release of biotherapeutics.

Technical Principle

The kit is based on the TaqMan probe-based real-time qPCR technology, which achieves specific and quantitative detection of 293 DNA through three core components:

1. Specific Primers: Target highly conserved gene regions of 293 cells (e.g., the adenovirus E1A gene, a unique genetic marker of 293 cells). These primers have no cross-reactivity with human genome DNA, microbial DNA, or other common host cell DNAs (such as CHO, Vero cells), ensuring detection specificity.

2. Fluorescent Probe: A dual-labeled TaqMan probe that binds to the target sequence between the two primers. The 5' end is labeled with a reporter fluorescent dye (e.g., FAM), and the 3' end is labeled with a quencher dye (e.g., BHQ1). In the absence of target DNA, the reporter dye is quenched, and no fluorescence is emitted; when the target DNA is present, the Taq enzyme's 5'→3' exonuclease activity cleaves the probe during PCR amplification, releasing the reporter dye and generating a fluorescent signal.

3. Optimized qPCR System: The kit contains a pre-mixed qPCR Master Mix (including Taq DNA polymerase, dNTPs, Mg²⁺, and PCR buffer) with high amplification efficiency and anti-inhibition ability. It can effectively resist PCR inhibitors in complex sample matrices (e.g., protein aggregates, surfactants in biopharmaceutical products), ensuring stable amplification performance.

The fluorescent signal intensity is proportional to the amount of amplified target DNA. By comparing the Ct (Cycle Threshold) value of the sample with the standard curve (established using known concentrations of 293 DNA standard), the absolute content of residual 293 DNA in the sample can be accurately calculated.

Key Features & Advantages

1. High Specificity:

◦ Targets unique genetic loci of 293 cells, with no cross-reactivity with human DNA, CHO cell DNA, E. coli DNA, or yeast DNA (verified by cross-reactivity tests with 10 ng of non-target DNA).

◦ The combination of specific primers and TaqMan probes reduces non-specific amplification, ensuring false positive rates < 0.1%.

1. Ultra-high Sensitivity:

◦ The minimum detection limit (LOD) is as low as 0.1 pg/mL, and the minimum quantification limit (LOQ) is 1 pg/mL, which is far lower than the international regulatory requirement (≤ 10 ng/dose for residual host cell DNA in biopharmaceuticals).

◦ Even trace amounts of 293 DNA residues in high-concentration protein samples (e.g., 1 g/L monoclonal antibody solutions) can be accurately detected.

1. Wide Linear Range:

◦ The linear detection range covers 1 pg/mL to 100 ng/mL, with a linear correlation coefficient (R²) > 0.995 and amplification efficiency between 90% and 110%.

◦ It can be directly used for samples with different residual DNA content without multiple dilutions, simplifying experimental operations.

1. Fast Detection & Easy Operation:

◦ The entire experimental process (including sample pretreatment, qPCR amplification, and data analysis) can be completed within 3 hours, significantly shortening the detection cycle compared to traditional dot blot or Southern blot methods (which take 1-2 days).

◦ The kit provides pre-mixed reagents (Master Mix, primers/probe mix, standards) and a detailed operation manual, reducing the risk of manual errors and enabling standardization of detection procedures.

1. Strong Anti-interference Ability:

◦ The optimized buffer system contains PCR enhancers and inhibitor scavengers, which can effectively eliminate the interference of common substances in biopharmaceutical samples (e.g., bovine serum albumin, polysorbate 80, sodium chloride) on qPCR reactions.

◦ Validated for compatibility with various sample matrices, including cell culture supernatants, purified protein solutions, and vaccine formulations.

1. Reliable Quality Control:

◦ Each batch of kits undergoes strict quality verification, including performance tests (sensitivity, linearity, specificity), stability tests (accelerated stability, long-term stability), and batch-to-batch consistency tests (CV < 5% for replicate detections).

◦ The kit is accompanied by a Certificate of Analysis (CoA) that records detailed quality data, meeting the traceability requirements of GMP (Good Manufacturing Practice) systems.

Applications

The GeticoSEQ 293 DNA Residue Quantitative Kit is widely used in the biopharmaceutical industry and life science research, mainly in the following scenarios:

1. Quality Control of Biopharmaceutical Products:

◦ Quantification of residual 293 DNA in monoclonal antibodies (mAbs), recombinant therapeutic proteins (e.g., insulin, growth hormone), and viral vaccines (e.g., adenovirus vector vaccines) during production and final product release.

◦ Detection of 293 DNA residues in intermediate products (e.g., cell harvests, protein purification fractions) to optimize purification processes (e.g., DNAase treatment, chromatography conditions).

1. Research on Cell Therapy & Gene Therapy:

◦ Detection of residual 293 DNA in 293-derived viral vectors (e.g., adenovirus, lentivirus) used in gene therapy to ensure the safety of vectors for in vivo administration.

◦ Quantification of 293 DNA contamination in cell therapy products (e.g., CAR-T cells) to avoid potential risks of host cell DNA integration.

1. Bioprocess Development:

◦ Evaluation of the efficiency of DNA removal during the development of biopharmaceutical production processes (e.g., comparison of DNA residue levels before and after purification steps).

◦ Validation of analytical methods for residual host cell DNA, in compliance with regulatory requirements for method validation (e.g., specificity, accuracy, precision).

1. Academic Research:

◦ Detection of 293 DNA residues in experimental samples (e.g., cell culture supernatants, tissue homogenates) in studies involving 293 cells, ensuring the accuracy of research results (e.g., avoiding false positive signals caused by 293 DNA contamination in downstream experiments like PCR or sequencing).

Standard Operation Procedure (SOP)

1. Sample Pretreatment

• Protein-containing Samples (e.g., monoclonal antibody solutions): Take 100 μL of the sample, add proteinase K (provided in the kit) for digestion at 56°C for 30 minutes, then use the included DNA extraction kit to isolate and purify residual 293 DNA (elution volume: 50 μL).

• Viral Vector Samples: Take 200 μL of the vector solution, heat it at 95°C for 10 minutes to inactivate the virus, then proceed with DNA extraction as described above.

• Blank Control: Use ultrapure water instead of the sample to perform the same pretreatment steps to monitor cross-contamination during the experiment.

2. qPCR Reaction Setup

Prepare a 20 μL reaction system in a 96-well qPCR plate according to the following proportions:

• Standard Curve Preparation: Dilute the 293 DNA Standard (provided in the kit) to concentrations of 1 pg/mL, 10 pg/mL, 100 pg/mL, 1 ng/mL, 10 ng/mL, and 100 ng/mL, and set up duplicate wells for each concentration.

• Sample Wells: Set up duplicate wells for each pretreated sample to ensure data reproducibility.

• Negative Control: Add 5 μL of ultrapure water instead of sample DNA to monitor non-specific amplification.

3. qPCR Amplification

Run the amplification program on a real-time qPCR instrument (compatible with Applied Biosystems, Bio-Rad, Roche, etc.) as follows:

1. Pre-denaturation: 95°C for 5 minutes (activation of Taq DNA polymerase).

2. Amplification cycle (40 cycles): 95°C for 15 seconds (denaturation), 60°C for 30 seconds (annealing and extension, simultaneous collection of fluorescent signals).

4. Data Analysis

• Standard Curve Establishment: Use the qPCR instrument software to plot the standard curve with the logarithm of the 293 DNA standard concentration as the x-axis and the Ct value as the y-axis, and calculate the linear regression equation (y = ax + b) and R² value.

• Sample Quantification: Substitute the Ct value of the sample into the standard curve equation to calculate the concentration of 293 DNA in the purified sample DNA solution, then convert it to the residual 293 DNA content in the original sample according to the sample volume and elution volume used in pretreatment.

• Result Judgment: If the Ct value of the sample is greater than the Ct value of the LOQ standard (1 pg/mL), the residual 293 DNA content is below the quantification limit; if the Ct value is within the linear range of the standard curve, the result is valid and can be reported.

Storage & Shelf Life

• Storage Conditions: Store the kit at -20°C in a dark environment; avoid repeated freezing and thawing (it is recommended to aliquot the primers/probe mix and Master Mix into small volumes after the first thaw).

• Shelf Life: 12 months from the date of manufacture when stored according to the recommended conditions.

• Transportation: Transport the kit using dry ice to maintain the -20°C temperature, ensuring no temperature rise during transportation.

Technical Support

Shanghai Getico Biotechnology Co., Ltd. provides comprehensive technical support for the GeticoSEQ 293 DNA Residue Quantitative Kit:

• Pre-sales Consultation: Assist customers in selecting appropriate detection solutions based on sample types and regulatory requirements.

• After-sales Service: Provide troubleshooting for experimental problems (e.g., abnormal standard curves, high Ct values of samples) within 24 hours.

• Method Validation Support: Offer guidance on method validation protocols (including specificity, accuracy, precision, and robustness) to help customers meet regulatory submission requirements.

For more information, please contact Shanghai Getico Scientific Co., Ltd. via email (service@geticosci.com).