Expression systems
Expression systems
Expression systems for adenovirus
vector-based vaccines
Advaxia leads the industry in developing and optimizing cell-vector systems.
Well-engineered expression systems
are crucial for effective viral vaccines.
In the production of any vaccine or viral seed stock, a critical step is the careful selection of the expression system and the following generation of high-quality pre-GMP materials. The quality of these materials directly impacts the productivity and the efficiency of the entire manufacturing process, which in turn influences the quality of the clinical lots produced.
At Advaxia, we have spent years consolidating our expertise in the adenoviral platform, to generate prophylactic and therapeutic vaccines for Phase I, II and III clinical studies. Adenovirus vector-based vaccines are engineered to be replication deficient and can be manufactured in well-established cell lines containing the adenoviral E1 gene.
We utilize pre-GMP virus seed stocks as starting material for the clinical manufacturing of vaccine lots, generating all materials in our dedicated facility within adherent and/or suspension customer-specific cell lines. Our adaptable approach enables us to offer our clients the opportunity to outsource the entire development process of their expression systems to our laboratory.
Alternatively, our experts can plug into your pipeline at any intermediate step, working seamlessly with your in-house development team to provide a concierge level of tailored service.
Advaxia’s capabilities in
expression system development
Transfection of specially engineered plasmids into mammalian cells
Our team possesses decades of combined experience in introducing DNA plasmids into cells. Our method utilized liposome transfection — beginning by seeding adherent cells; then, once appropriate confluence is reached, transfecting cells with a mixture of DNA and transfection reagents. Following an incubation period, our team harvests the cells and utilizes them to amplify the gene of interest.
Isolation and amplification of genes of interest
Our team begins by collecting lysates from transfection and using them to generate amplification passages. During the first amplification passage, we infect cells with lysate from the transfection. Once the cells have reached full cytopathic effectiveness, we collect them and utilize them to generate further amplification passages. Once a detectable virus quantity has been produced, our team then infects cells at an optimal multiplicity of infection and isolates single clones through an array of industry-leading techniques, such as plaque picking and dilution-limiting. Once we have identified an ideal clone in terms of productivity and expression, we subject it to the minimum number of amplification rounds necessary to amplify it to a target-size pre-GMP seed stock — resulting in highly efficient progress toward process development studies, as well as the manufacturing of toxicology and clinical lots.
Optimization of cell-vector systems
Generation and characterization of the pre-GMP virus seed stock
We subject pre-GMP virus seed stock to extensive characterization, subjecting the virus to several amplification cycles, testing each cycle to verify the vector’s stability and to confirm that no genetic changes occur during the production process. This enables us to establish the suitability of every pre-GMP virus seed stock we generate for further use in clinical lot production.