The SARS virus

CDC

[BEIJING] Scientists have identified two human antibodies that neutralise the viral strains that caused the two outbreaks of Severe Acute Respiratory Syndrome (SARS) between 2002 and 2004.

These antibodies could be the first step in producing a treatment to disable the virus that causes SARS.

The research, conducted by a group of American, Australian and Swiss scientists, was published online in Proceedings of the National Academy of Sciences this week (3 July).

One of the antibodies was discovered from the blood sample of a patient who recovered from SARS, and another — m396 — was identified from the library of human antibodies developed from the blood of ten healthy volunteers.

Studies in mice and in vitro human cells with a sample of the virus isolated from the outbreak in humans showed that both antibodies are able to bind to and block the part of the SARS virus that allows it to attach to and enter cells, thus disabling the virus. Both antibodies also disabled a sample of the virus isolated from wild civets, but with less potency.

Further analysis of the structure of m396 suggested that it could successfully disable all known forms of the SARS virus.

But the researchers warn that it is possible that the SARS virus could mutate into an unknown form.

"The antibody could be useful against novel mutants but that is not guaranteed and cannot be predicted. It is likely but not 100 per cent sure," lead author Dimiter S. Dimitrov, from the US National Cancer Institute (NCI), told SciDev.Net.

Zhang Yong, a researcher at the Institute of Virology of the Chinese Centre for Disease Control, welcomed the research, saying it could provide a new preventive and emergent measure against a SARS outbreak.

But he told SciDev.Net that we must remain cautious because the SARS virus may have other ways of attaching to and entering human cells, and therefore may not be completely disabled by these antibodies.

SARS first emerged in the southern Chinese province of Guangdong in late 2002, and spread internationally in early 2003. The last occurrence was reported in China in mid 2004. In all, SARS killed 774 people, and infected more than 8,000 globally.

Currently, there is no treatment to specifically eliminate the SARS virus.

Separately, a group of Australian and Malaysian scientists reported that they have discovered an unknown virus that led to another acute respiratory disease.

The virus was isolated from a Malaysian patient and is believed to have crossed over from a bat.

Link to full papers in Proceedings of the National Academy of Sciences:

First study
Second study

References:
Proceedings of the National Academy of Sciences doi 10.1073/pnas.0701000104 (2007)