Surface Expression Vector for HPV Antigen Production
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Solution Overview
Problem
Current methods for producing HPV therapeutic vaccines face challenges in efficiently and economically expressing HPV antigens, particularly in developing countries, where cervical cancer prevalence is high, and existing technologies have limitations such as low antigen expression levels and purification issues in plant-based systems, and safety concerns with live viral vaccines.
Innovation Solution
A surface expression vector containing a repE mutant gene, a promoter, and a poly-gamma-glutamate synthetase complex gene is used to stably and constitutively express HPV antigen proteins on the surface of recombinant lactic acid bacteria, enabling high-level expression and production of HPV antigens for vaccine development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasmid vectors with standard promoters are used for HPV antigen expression, then the expression system is simple and easy to construct, but the antigen expression level is low and production efficiency is insufficient
Solution Approach 1:
The patent combines multiple functional elements into a single integrated expression vector: the repE mutant gene for plasmid replication control, the constitutive promoter P5 for continuous transcription, the pgsA gene for surface anchoring, and the HPV antigen gene (E6/E7 or L1). This merging of replication control, promotion, anchoring, and antigen expression functions into one vector enables high-level constitutive expression of HPV antigens on bacterial surfaces without requiring separate systems for each function.
Solution Approach 2:
The patent modifies key parameters of the expression system by using a repE mutant gene that alters plasmid copy number control, enabling constitutive high-level expression. The mutation in repE changes the replication dynamics from regulated to constitutive, allowing continuous antigen production without induction steps, thereby significantly increasing overall antigen yield and expression consistency.
2Reliability
If live viral vaccines are used for HPV prevention, then immune response can be induced, but safety concerns arise from excessive viral replication and lengthy commercialization processes
Solution Approach 1:
The patent uses recombinant bacteria as temporary, disposable production systems rather than creating live viral vaccines. The bacteria are engineered to produce and display HPV antigens on their surfaces, then are used as vaccines themselves or as production platforms for antigen purification. This approach eliminates the need for complex viral replication and extensive clinical trials required for live viral vaccines, enabling faster commercialization while maintaining safety through the use of non-pathogenic bacterial hosts.
3Ease of manufacture
If plant-based systems are used for HPV antigen production, then production can be achieved, but antigen expression levels are low and purification problems occur
Solution Approach 1:
The patent introduces a poly-gamma-glutamate synthetase complex gene (pgsA) as an intermediary element that mediates the anchoring of HPV antigens to the bacterial cell surface. The pgsA gene encodes enzymes that produce poly-gamma-glutamate chains, to which the HPV antigens are covalently attached. This intermediary mechanism ensures high-level expression and stable surface display of antigens, overcoming the low expression and purification issues encountered in plant-based systems.
Data Source
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AI summary
The present invention relates to a surface expression vector for preparing HPV vaccines, in which the surface expression vector contains a gene encoding a repE mutant protein having an amino acid sequence of SEQ ID NO: 1, a promoter, a poly-gamma-glutamate synthetase complex gene, and a gene which is linked with the poly-gamma-glutamate synthetase complex gene and encodes a tumor induction-associated antigen protein of human papillomavirus. The present invention provides an expression vector constitutively expressing a high level of the human papillomavirus (HPV) antigen protein. Also, the invention provides recombinant lactic acid bacteria, transformed with the expression vector and expressing the HPV antigen protein on the surface thereof, and a composition comprising the recombinant lactic acid bacteria. The recombinant lactic acid bacteria and the composition are very effective as a vaccine for the treatment of cervical cancer, because they can be applied orally or directly to the vagina.