Antibodies from Sars patients offer new treatment

WASHINGTON - Antibodies from patients who have recovered from SARS can be quickly found and used to treat others with a new method developed by Swiss and US scientists, the researchers reported on Monday.

Tests on mice suggest the treatment can be adapted for use against any new infection -- offering a fast method to fight emerging disease and, perhaps, biological attacks.

Writing in the journal Nature Medicine, the researchers said they also learned which of the immune system proteins, known as antibodies, are the most effective in subduing the virus that causes SARS.

Severe Acute Respiratory Syndrome emerged in China in 2002 and swept across many countries killing about 800 people. It appears to have been contained but scientists warn many more such pathogens are waiting to emerge.

The disease is caused by a never-before-seen virus and although some work has been done to develop a vaccine, there is no good treatment for the illness.

"A vaccine may provide little benefit to someone already infected," said Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, which helped sponsor the study.

So the researchers explored an approach called passive immune therapy -- using the immune cells of patients who have successfully fought off the disease. The problem is finding the right cells and using them effectively.

Elisabetta Traggiai, and Dr Antonio Lanzavecchia of the Institute for Research in Biomedicine in Bellinzona, Switzerland, developed a new way to do it.

They took some of the cells that make antibodies, known as B cells, from a recovered SARS patient. So-called memory B cells recognise a bacterial or viral invader and generate antibodies designed to recognise that particular microbe.

They attached a short stretch of synthetic DNA that mimics some of the DNA found in bacteria and viruses. This reactivated some of the B cells, and they began pumping out different antibodies, many of them specific to SARS.

The researchers then examined these antibodies and found the ones that worked best against SARS.

Dr Kanta Subbarao and Dr Brian Murphy at the NIAID then tested the new antibodies in mice and found they prevented the virus from multiplying in the respiratory system.

- REUTERS