Establishment and application of plasmid reference for detection of residual DNA of early region 1A protein and simian virus 40 large T antigen
10.13200/j.cnki.cjb.004467
- VernacularTitle:早期区域1A蛋白和猿猴病毒40大T抗原残留DNA检测用质粒参考品的建立及应用
- Author:
BI Hua
- Publication Type:Journal Article
- Keywords:
Plasmid DNA;
Reference material;
Digital PCR;
Ultraviolet spectrophotometry
- From:
Chinese Journal of Biologicals
2025;38(04):418-426
- CountryChina
- Language:Chinese
-
Abstract:
Objective To construct a plasmid reference for the detection of residual DNA from early region 1A(E1A) protein and simian virus 40 large T antigen(SV40LTA), and to explore a digital PCR(dPCR)-based analytical technique for copy number calibration of plasmid reference to quantify plasmid reference accurately, thereby providing a new idea for host cell DNA residual detection in biological products.Methods The plasmid pUC19-E1A-SV40LTA was constructed, and the whole gene was synthesized and then amplified to obtain sufficient reference plasmid. The digital PCR system was employed to determine the copy numbers using double fluorescence channels of E1A and SV40LTA primer-probe sets, respectively.The reference material calibrated by digital PCR was subsequently applied to qPCR to establish a method for detecting the specific E1A and SV40LTA sequences. The developed qPCR assay was systematically validated for plasmid reference linearity, accuracy, limit of quantification(LOQ), precision, specificity, applicability, and stability. Furthermore, the established qPCR system was utilized for the detection of recombinant adenovirus(rAdV) sample and recombinant adeno-associated virus(rAAV) sample.Results The copy numbers of E1A and SV40LTA targets in the plasmid reference were found to be essentially consistent through digital PCR using dual fluorescence channels. The detection values detected by E1A and SV40LTA primer-probe sets were 3. 55 × 109and 3. 48 × 109copies/μL, respectively. The coefficient of variation(CV) of these two values was 1. 42%, and the mean value of 3. 51 × 109copies/μL was taken as the calibration value of digital PCR.The qPCR system established by using digital PCR to calibrate copy number exhibited good linearity, accuracy, LOQ, precision, specificity, applicability and stability, and the recovery rates for rAdV and rAAV samples were between 70% and130%.Conclusion A reference plasmid for detecting E1A and SV40LTA residues in biological products was established,and a more sensitive and accurate digital PCR method was introduced for quantification, which can be used to detect the residual DNA of E1A and SV40LTA in gene therapy products produced with HEK293 and HEK293T as host cells.
