SARS vaccine caused liver damage in animals: lab

[Guest guest]

[Liver damage is the number one problem associated with pharmaceuticals

- leading to all sorts of systemic problems and iatrogenic

(physician-caused) disease]

 

SARS vaccine caused liver damage in animals: lab

http://www.canada.com/national/story.html?id=c1c2e091-e92e-488c-9294-4d03e06a4d7\

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Helen Branswell

Canadian Press

 

Sunday, November 28, 2004

 

TORONTO (CP) - A SARS vaccine designed by Canadian scientists triggered

severe liver inflammation when tested in ferrets - an unexpected problem

that should give pause to others working to develop a vaccine against

the disease.

 

The team, which reported its findings in the Journal of Virology,

stumbled upon the problem by accident when one of the scientists

insisted on running unplanned blood chemistry tests on the vaccinated

ferrets.

 

The director of the Canadian SARS Research Network says the results are

a red flag to all working on vaccines for the disease.

 

" This is really important because it really is saying: proceed

cautiously in people, " said Dr. Mark Loeb, an infectious disease

specialist at Hamilton's McMaster University. Loeb was not involved in

the work.

 

The team was drawn from the Canadian Science Centre for Human and Animal

Health, the Winnipeg complex which houses the National Microbiology

Laboratory and the National Centre for Foreign Animal Disease.

 

Research scientist Jingxin Cao constructed the recombinant vaccine by

genetically modifying a pox virus to produce a protein - called the

spike protein - which is made by the SARS coronavirus. The spike protein

is the key protein on the SARS virus that triggers an immune response.

 

Cao chose the modified pox virus, called MVA, because it has been widely

- and safely - used in development of other vaccines.

 

" It's really safe, even in the so-called immune compromised, like AIDS

patients, " he said in an interview.

 

The team then put the vaccine to the test, vaccinating ferrets, which

are believed to suffer disease similar to that experienced by humans who

contract SARS. They then waited to see whether the animals developed

antibodies to the virus when they were exposed to SARS in what's called

a challenge test.

 

On that front, things went smoothly.

 

" We had quite nice antibody levels against this protein, " said Hana

Weingartl, head of special pathogens in the centre for foreign animal

disease.

 

But then colleague Markus Czub insisted on running the blood chemistry

tests and found evidence of severe hepatitis - inflammation of the

liver. Autopsies on the animals confirmed the finding.

 

And there was another hitch. Their control ferrets - the unvaccinated

animals - didn't show signs of disease, leading the team to wonder

whether they are indeed a good model for human SARS.

 

" They certainly do replicate the virus but they did not get sick, "

Weingartl said.

 

That isn't the experience of another Canadian researcher working on a

SARS vaccine.

 

Brett Finlay, a molecular biologist at the University of British

Columbia, said ferrets his team tested developed symptoms similar to

human SARS.

 

" They got sick; they got lung disease, just like people do, " said

Finlay, whose team worked on different kinds of vaccines, including one

based on a killed coronavirus and another on a modified adenovirus.

 

" You crack open the lungs and it's all inflammed and yucky, just like

you see in SARS. "

 

His team's results are not yet published, so they haven't been confirmed

by outside experts through a scientific journal's peer review process.

But he says they did not see liver inflammation - and they checked.

 

" We did not see what they saw. We'd heard about that, so we were looking. "

 

Finlay agreed with Loeb that all teams working on a SARS vaccine will

have to check for liver inflammation from now on.

 

" We'd be dumb not to, " he insisted.

 

As for the Winnipeg team, they cannot say whether the problem they saw

relates strictly to their vaccine or is indicative of a wider challenge

to the development of a SARS vaccine.

 

" We don't know whether or not this association of vaccination with

enhanced hepatitis is only related to the MVA base, " Cao said. " Could be

if you tried a different way - for example, adenovirus-based, another

virus based - you won't see this. We don't know. "