COVID-19 SPECIAL

Getting human body to produce part of coronavirus to fight it

Assistant Professor Danielle Anderson and laboratory assistant Velraj Sivalingam working on the virus that causes Covid-19 in a lab at Duke-NUS Medical School.
Assistant Professor Danielle Anderson and laboratory assistant Velraj Sivalingam working on the virus that causes Covid-19 in a lab at Duke-NUS Medical School.PHOTO: DUKE-NUS MEDICAL SCHOOL

Duke-NUS Medical School is working with American medicine company Arcturus Therapeutics on a Covid-19 vaccine which involves getting the human body to produce part of the Sars-CoV-2 virus.

Professor Ooi Eng Eong, deputy director of the school's emerging infectious diseases programme, explained that it is all about teaching the immune system to "recognise" the virus.

He told The Straits Times that ideally, you use the whole virus. Like how you would show a video of a criminal, not just a photo.

"You'd probably recognise him better if I showed you a video of him and you see how he moves, if he has a limp.

"So if you use the whole virus, our immune system will recognise the virus much better because it sees the whole life cycle of the virus."

However, given how deadly Sars-CoV-2 can be, as well as the specialised laboratory conditions required to handle it, developing a vaccine using the entire virus was out of the question for Prof Ooi.

An alternative is to use a dead virus instead. But Prof Ooi said: "The problem is that in the killing process, we also destroy some parts of the (virus) protein. So effectively, you distort the picture, and you're not recognising the real (virus)."

The vaccine that Duke-NUS and Arcturus Therapeutics are working on, however, is known as an mRNA vaccine. This involves injecting genetic material called mRNA, which encodes part of the virus, into a person. The mRNA will then be absorbed by the body's cells, which begin manufacturing a protein similar to that of the virus - without actually infecting the person.

"The protein is then displayed on the cell, just like if it was infected. And that's when the antibodies respond and recognise this part of the virus," said Prof Ooi, who added that this teaches the immune system to fight against it.

As the protein will replicate itself inside the body, giving the immune system more time to recognise it, only a small dose is needed.

Using mRNA instead of a live virus also allows the vaccine to be more easily produced on a large scale, as this removes the need for a highly specialised laboratory setup.

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Senior vice-dean at Duke-NUS' Office of Research Patrick Casey said that Arcturus Therapeutics approached the school in February to work on the vaccine.

"We have the expertise, we have the people who knew what they're doing, and the outside world has confidence in their ability to really do this well," he said.

Arcturus Therapeutics is developing the vaccine and testing it on animal models, while Duke-NUS is responsible for analysing the test results and determining the effectiveness of the vaccine.

 
 
 

Prof Ooi said that in the five weeks or so since the start of the tests, results have been promising. "The amount of antibodies that one dose of the vaccine has been generating is much better than what patients generate after Covid-19. We're quite pleased with the results," he said.

The research teams hope to start dosing humans with the vaccine by September.

Prof Casey said: "The world's record in producing a vaccine is five years, but hopefully someone will shatter that this year. And we could be the ones."

Prof Ooi added: "I think it'd be great if this vaccine helps to bring life back to normal for people."

 
A version of this article appeared in the print edition of The Straits Times on May 19, 2020, with the headline 'Getting human body to produce part of coronavirus to fight it'. Subscribe