Four-Plasmid Lentiviral Packaging for Higher-Titer CAR Cell Transfection
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Solution Overview
Problem
Current lentiviral vector systems for transfecting T cells have low transfection titers and safety concerns, necessitating higher doses with increased costs and residual substances, and the optimal ratio of plasmids for a four-plasmid packaging system to enhance transfection efficiency and safety is not established.
Innovation Solution
A four-plasmid packaging system comprising a target plasmid and three helper plasmids, specifically Seq1, PMD2.G, pMDLg-pRRE, and pRSV-Rev, at optimized ratios (e.g., 2-6:1-1.5:1-3:1-1.5) to increase lentivirus transfection titer and ensure high safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lentiviral vector system is used for transfecting T cells, then the transfection process can be performed, but the transfection titer is low and safety concerns arise
Solution Approach 1:
The patent divides the packaging system into four separate plasmids instead of using a conventional three-plasmid system. This segmentation allows for better control of viral production, reducing safety risks while maintaining or improving transfection efficiency. The four plasmids are: (1) a transfer plasmid containing the CAR gene, (2) a packaging plasmid, (3) an envelope plasmid, and (4) a helper plasmid, each performing a specific function in the viral packaging process.
Solution Approach 2:
The patent optimizes the ratio of the four plasmids to achieve the best transfection results. By adjusting the relative amounts of each plasmid, the system maximizes transfection titer while minimizing safety concerns. The optimal ratio determined in the patent allows for efficient viral production without excessive residual substances.
2Productivity
If a higher dose of lentivirus is used to achieve ideal T cell transfection effect, then transfection efficiency improves, but costs increase and residual substances and safety issues worsen
Solution Approach 1:
The patent determines the optimal multiplicity of infection (MOI) and plasmid ratios to achieve ideal transfection efficiency without using excessive virus doses. This parameter optimization ensures high transfection efficiency while minimizing residual substances and associated safety risks.
3Productivity
If the four-plasmid packaging system is used, then transfection titer can be increased, but the optimal ratio of plasmids for packaging lentiviral vectors is not yet determined
Solution Approach 1:
The patent systematically tests and determines the optimal ratio of the four plasmids for the packaging system. By establishing specific ratio ranges, the patent simplifies the complexity of plasmid preparation while maximizing transfection titer. The determined ratios provide a standardized protocol for reproducing high-efficiency transfection results.
Data Source
AI summary
Provided in the present disclosure is a method for using a four-plasmid system to prepare modified immune effector cells. The method comprises: forming a lentivirus by using four plasmids within 293T cells, extracting and obtaining the lentivirus, then transfecting immune effector cells by using the lentivirus, and expressing a chimeric antigen receptor. Also provided in the present disclosure is a use of the immune effector cell obtained by using the described method and of a composition containing the immune effector cell.