Australian researchers discover how body’s immune system fights coronavirus COVID-19


Australian Broadcast Corporation News
March 16, 2020
By Sophia Scott, Penny Timms, and Loretta Florance

Katherine Kedzierska’s team analysed the blood of one of Australia’s first coronavirus patients to find out how the immune system responded.(ABC News: Loretta Florance)

Key points:
Researchers found the body’s immune system fights coronavirus in the same way as the flu
The findings will help scientists develop an effective vaccine
It could also help identify new treatments

Understanding how an enemy works is the first step towards defeating it.

That is why scientists have been scrambling to find out what coronavirus does to the body.

Now for the first time, researchers at the Peter Doherty Institute for Infection and Immunity understand how humans fight off the virus.

Laboratory head Katherine Kedzierska found people’s immune system responded to coronavirus in the same way we try to fight the flu.

“The immune cell populations we have seen emerging before patients recover are the same cells that we see in influenza,” she said.

Very little is known about how coronavirus acts, as it’s so new.

In this new research, scientists have taken the blood samples of one of Australia’s first patients diagnosed with coronavirus and identified the antibodies recruited by the body to fight the illness.

“It’s the first paper that shows the body can give immunity and fight back and recover,” researcher Carolien van de Sandt said.

“Because this is a new virus, we didn’t know how the body would respond.”

The scientists are hopeful their findings help in the race for an effective vaccine.

“This information will allow us to evaluate any vaccine candidate as in an ideal world the vaccine should mimic our body’s immune response,” Professor Kedzierska said.

Why was Australia first to analyse the body’s response?
The Victorian researchers took blood samples from a woman in her 40s, one of the first patients diagnosed with coronavirus in Australia.

She had been in Wuhan in China and was admitted to a Melbourne hospital with symptoms including lethargy, sore throat, dry cough and a fever.
Tests revealed she had COVID-19.

Doctors took four blood samples before and after her recovery.

“We found in this patient at three days, we could see emergence of immune cells in the blood,” Professor Kedzierska said.

“Based on our experience with patients with influenza, we could predict recovery and that’s exactly what happened in COVID-19.”

The Doherty Institute’s infectious disease specialist Irani Thevarajan has been planning for a situation like this for years.

“We’ve been sitting here knowing that different disease outbreaks will happen, and that when they do happen, we want to be able to respond really quickly,” Dr Thevarajan said.

She heads up a “research preparedness platform”, which has enabled researchers and major Victorian hospitals to work together from the arrival of the first patient.

“It’s been set up so that everything from start to end — patient identification to sample analysis and storage — the framework is there ready to go,” she said.

“You can imagine there’s some ethical consideration when taking samples from patients and information from patients, so the ethical framework was there as well.”

With all the logistics fast-tracked, she said the researchers were uniquely placed to get straight to work in a way they never have before.

“Sometimes the delay could have been months … it wouldn’t have been from patient to research in four weeks.”

Does getting coronavirus give you immunity?
Getting the body to turn on the immune system to fight off a disease like coronavirus is important.

With SARS in 2003, more people died because they could not mount a good immune response.

“Our study is an important step in understanding how our body recovers from a mild to moderate infection of COVID-19,” Professor Kedzierska said.

Eight out of 10 people who contract coronavirus will have mild to moderate symptoms.

Using the new research, the scientists are hoping to use markers in the blood to screen patients to see if they are likely to develop more serious symptoms.

“Then you could say upfront, this would be a severe case, or this will probably be a milder case,” Dr van de Sandt said.

“Then you could alter their care to what the patient might need.”

Carolien Van de Sandt’s research could help medical teams work out how severely different patients would react to the virus.(ABC News: Loretta Florance)

But it is too early to tell whether getting COVID-19 once gives you immunity from getting it again.

“We know we can generate immune responses to the virus,” Professor Kedzierska said.

“The next question is whether that immune response gives people immunity for weeks or months or years so we are protected.”

Professor Kedzierska said scientists would only know this after checking in with patients in the coming months.

But the findings could help doctors find effective new treatments.

Professor Kedzierska and Dr van de Sandt say their paper, published in Nature, is an exciting development for scientists trying to understand coronavirus.(ABC News: Loretta Florance)

“Understanding what’s lacking or different in people with severe or fatal COVID-19 disease could lead to new therapeutics,” Professor Kedzierska said.

Scientists will now map the immune system of a bigger group of patients including those with more severe symptoms.

“We are very curious to see what happens in those patients and see what part of the immune response is not getting activated,” Dr van de Sandt said.

Their paper has now been published in Nature Medicine, giving researchers around the world the chance to apply their techniques to the blood samples of others.

“For the scientific community, it’s very exciting to have this,” Dr van de Sandt said.