Antibodies produced by shark immune systems could be used to detect human pathogens

A recent discovery shows that antibodies produced by shark immune systems could be used to detect a range of human pathogens some of which have the potential to be used as biological warfare agents.

Melbourne Scientists, Drs Victor Streltsov and Stewart Nuttall in the CRC for Diagnostics at CSIRO Health Sciences and Nutrition, have determined the three-dimensional molecular structure of a new class of antibodies from sharks using X-ray crystallography.

Dr Nuttall says the shark antibodies have now been designed and produced entirely in the laboratory to create highly stable new clinical reagents.

"This makes them ideal for use in diagnostics, especially as they have also evolved to a small size," he says.

"As a result, we now have an opportunity to produce antibodies which can be used to detect infectious disease agents like SARS and anthrax, and for environmental science and biotechnology applications."

Dr Streltsov says defining the structures was challenging, particularly as they are so different from other immune-system molecules.

"There were also many subtle changes acquired over millions of years of evolution, which proved that these shark antibodies have a unique evolutionary history," he says.

"Over the last 500 million years, the shark immune system appears to have co-opted a particular type of cell-surface protein to its own use, creating a novel additional class of antibodies completely unlike those seen in humans."

The discovery and a description of new antibodies obtained from wobbegong sharks (Orectolobus maculatus), was published this week in the prestigious journal, Proceedings of the National Academy of Sciences USA.

CRC Scientific Director and co-author of the article, Dr Peter Hudson, says the publication of the findings should prove to be an important milestone in increasing our understanding of the evolution of the immune system.

"Defining the antibodies' structures will enable the research team to design a revolutionary new class of molecules for clinical diagnosis and therapy, with important implications for biowarfare defence," Dr Hudson says.

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