Virus mimic used to create safe vaccines for mosquito-borne diseases

A virus which can be “dressed up” by researchers to masquerade as other viruses is helping to develop new, more effective vaccines.

Researchers from the University of Queensland and QIMR Berghofer Medical Research Institute have discovered the properties in the Binjari virus – a virus which affects mosquitoes but which is harmless to humans.

UQ’s Dr Jody Hobson-Peters said the team discovered that the Binjari virus could have its “surface” manipulated so that it resembled other viruses, but remained harmless to humans.

“We exchange the genes which form the outer coat of the virus so that it looks identical to the virus we’re trying to emulate,” Dr Hobson-Peters said.

“But all of the replication machinery of the virus is still that of the Binjari virus, and that gives the safety level, because having all of that replication machinery of Binjari means the chimeric virus can’t replicate in human cells.”

When the chimera Binjari virus cells are used in vaccines, they prompt the immune response for the virus they are imitating, without the risk of that virus causing actual harm.

Binjari is part of a group of similar viruses which also includes dangerous mosquito-bourne human diseases such as dengue fever, Zika, and Japanese encephalitis.

Just last week a Queensland hairdresser was diagnosed with Japanese encephalitis after being placed in a coma following a holiday in Bali.

Working with live viruses for research and vaccine production is difficult because of the risk of the virus breaking biocontainment protocols, however the chimeric Binjari virus is much safer to work with because it doesn’t affect humans.

Professor Andreas Suhrbier, from QIMR Berghofer, said they hoped to investigate further whether the technique used in this work could be adapted for other viruses.

“The main advantage of this system is that it is safe,” Professor Suhrbier said.

“These hybrids cannot infect humans, meaning that manufacture of vaccines and diagnostic reagents don’t require the strict and expensive biosecurity infrastructure ordinarily needed to grow these pathogenic viruses.”

Dr Hobson-Peters said the fact that it was relatively easy to re-dress the Binjari virus meant they could develop chimera viruses extremely quickly, reducing the time it took to respond to outbreaks.

“If a new one of these viruses appeared, we could have a chimeric virus up and running within a few weeks, which is quite astounding,” she said.

Developing viable and safe vaccines for viruses spread through mosquitoes would be a major medical breakthrough, with vaccine coverage for the disease group still very limited.

There are currently no commercially available vaccines for Zika virus, although there are a number in clinical trails.

There is one vaccine available for dengue fever, dengvaxia, however it has severe side effects in some cases resulting in limited use.

The research has been published in the journal Science Translational Medicine.