Prototype vaccine for West Nile virus

Brisbane's Replikun Biotech has signed a licence agreement with UniQuest, the University of Queensland's commercialisation arm, to develop a new vaccine technology for West Nile virus.

The technology is based on research by UQ's Associate Professor Alex Khromykh and Dr Roy Hall and involves a developmental vaccine based on a modified form of the Kunjin virus, a benign flavivirus endemic to northern Australia.

The new technology will complement Replikun's core technology platform, Kunjin replicon gene delivery, the company's COO, Dr Lavinia Proctor said.

This technology provides a novel, persistent gene delivery system, which is anticipated to be suitable for immunotherapy, vaccine development and recombinant protein production, she said.

The Kunjin replicon is a self-replicating piece of RNA derived from the RNA genome of the Kunjin virus. It incorporates a vaccine or immunotherapy gene in place of deleted Kunjin virus structural genes.

The company said the removal of the Kunjin virus structural genes ensures that the Kunjin replicon cannot produce infectious particles. The Kunjin replicon retains the non-structural protein genes and several other elements essential for replicon self-replication.

The Kunjin replicon is well tolerated by cells, allowing vaccines to persist. Persistent vaccine antigen expression from the Kunjin replicon, combined with relatively low attendant inflammation, supports the formation and maintenance of protective immune responses, the company said.

Replikun is also developing a cancer immunotherapy candidate and a therapeutic HIV vaccine, both based on the Kunjin delivery system.

Under the agreement, Replikun will be responsible for all further development and commercialisation of the vaccine technology and will pay royalties to UniQuest on sales of licensed products.

West Nile virus has caused more than 1000 deaths in the US since it emerged in 1999 and is a growing problem in Europe. Khromykh and colleagues are also researching whether this type of vaccine could also be used against other flaviviruses such as dengue, tick-borne encephalitis and Japanese encephalitis viruses.