Fighting chikungunya

Singapore PhD candidate Melissa Tan developing a vaccine for mosquito-borne virus

Singaporean PhD student Melissa Tan (Bachelor of Medical and Pharmaceutical Sciences with Honours 2012) is developing a vaccine for chikungunya, a severe mosquito-borne virus re-emerging in Asia and the Caribbean with a heightened risk of spreading to Australia.

Melissa is developing a chikungunya vaccine in her project with the School of Pharmacy and Medical Sciences.

Symptoms of chikungunya virus include fever, joint pain, headaches and rashes which can drag on for months and become severe and disabling.

Spread by mosquitoes, the virus can exacerbate pre-existing health conditions such as cardiac and liver disease, and worsen neurological conditions. Despite the severity of the illness there is no vaccination or cure, and to make matters worse, conditions are building to make Australian outbreaks more likely.

“There’s increased risk now because of outbreaks in places like Asia and the Caribbean, and with so many Australians travelling to these areas the possibility of a local outbreak is heightened,” says Melissa.

“Plus we’ve got carriers such as Asian tiger mosquitoes and yellow fever mosquitoes residing in Queensland and the Torres Strait.”

Adding to the urgency, a recent mutation in the virus has allowed chikungunya to be carried by mosquitoes in temperate and urban environments.

Against this backdrop, Melissa’s research seeks to construct an efficient chikungunya vaccine that can be rolled out cheaply, rapidly and in large quantities, and be stable enough to allow periods of storage.

Her research is benefiting from a UniSA partnership with biotech company Sementis, which has been collaborating with the Experimental Therapeutics Laboratory headed by Associate Prof John Hayball. The collaboration is providing Melissa with access to development approaches and sophisticated, time-saving technology.

“We are following the Sementis approach of using their novel SCV platform technology for our vaccine development,” she says.

“We modify the SCV platform to include proteins specific to chikungunya.

“The hope is that we can get it to mimic chikungunya, and that the body will respond by building immunity.

“Other researchers are looking at creating a vaccine using different methods, but many of these are expensive because of factors such as licensing. Ours has potential to be very cost-effective.”

Having just commenced the third year of her PhD, Melissa is nearing completion of vaccine construction. The next step is rigorous preclinical testing, with an eye towards possible commercialisation down the track.

“We sent some of our vaccine to Queensland for analysis with live virus. Tests on mice showed they were protected against debilitating effects of chikungunya,” Melissa says.

“This was really encouraging, and we are now preparing to publish.

“We’ll be running lots of tests in the months to come to look at the body’s response.

“We’ve got all these resources here, including a new FACSAria fusion sorter, which automates cell sorting and helps save weeks and weeks of manual labour,” she says.

“This is a great opportunity to work on an exciting vaccine with the potential to help millions of people worldwide.”

The original article was published in UniSA’s Research Edge newsletter.

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