The USA's Nature Technology has launched an improved delivery technology for DNA vaccines that is now available for license by companies working in this fast-growing area.
The system, called RapidVACC, "allows us to rapidly deploy vaccines from modular genes, joined together like Lego toys," according to Jim Williams, vice president of R&D at the firm.
DNA vaccines provide a new means of immunising humans using genetic materials, delivered using a vector, that are expressed by the recipient's own cells. This means that there is greater control over the immunisation process, because the investigator determines which antigens to use, where to elicit the response (e.g. in skin or muscle), which cytokines (if any) are to be co-expressed and whether to use immunostimulatory DNA sequences to modulate the type of response. The duration of the response can be controlled by repeated exposure to the genes, which are expressed transiently.
"Until now, the above approach was difficult or impossible, because it is very hard to make large recombinant genes with multiple epitopes located in a single protein, according to Williams.
Nature Technology's scientists have optimised a DNA vaccine delivery platform to outperform previous state-of-the-art vectors. This has been achieved using several emerging technologies, but particularly the company's proprietary Gene Self-Assembly (GENSA) technology, which saves sub-cloning steps by recombining genes and DNA fragments simultaneously.
"Optimised vectors should overcome current technical limitations, including effectiveness, safety, and productivity," said company chief executive and chief scientist, Clague Hodgson. Nature Technologies' vaccines contain novel DNA origins of replication that allow up to three times as much vaccine DNA to be produced per cell - a critical cost and purity enrichment factor for the massive immunisations that will be needed to treat infectious diseases and cancer, according to Williams.
"This also permitted us to screen and select the best from many possible candidate components, and has resulted in a versatile and efficient vaccine platform that can potentially be applied to many pathogens," he added.
The Food and Drug Administration has published guidelines that served as a starting point for Williams' work, which was presented on 7 June at the annual meeting of The American Society for Gene Therapy.