Breakthrough could help protect against the use of smallpox by terrorists

Jun 9 2004

Researchers at the ANU John Curtin School of Medical Research have identified proteins that determine which mice succumb to mousepox and which do not. The new insights into the immune response of mice to the mousepox virus could enable scientists to improve treatment for poxvirus infections, including smallpox.

The research team, led by Dr Gunasegaran Karupiah, are the first in the world to identify the regulatory proteins, known as cytokines, which occur only in resistant individuals.

This finding raises the possibility of identifying those humans who would be at risk if exposed to smallpox, enabling extremely effective targeting for vaccination programs to prevent or treat the disease.

A coordinated vaccination campaign would significantly increase the number of people who could be protected, with a particular focus on health workers who would inevitably be involved in treating victims of a bioterrorism attack.

“This is an important step towards better protection from the threat of smallpox for health workers and the general community,” Dr Karupiah said.

Scientists know relatively little about the immune response to smallpox, primarily because the virus has been all but eradicated for years.

“Smallpox was one of the biggest human scourges, killing up to thirty per cent of the populations it hit and yet, because it was successfully eradicated, no one was interested in understanding how individuals recovered. But now, of course, the interest is back because of the threat of bioterrorism.”

The immune system of mice that are resistant to mousepox infection generate distinct types of cytokines, or regulatory proteins, to provide immunity. The three crucial cytokines are: interferon gamma (IFN-g), interleukin-2 (IL-2), and tumor necrosis factor (TNF).

In contrast, strains of mice susceptible to infection produce little or none of these cytokines, but produce a separate variety, called IL-4.

The findings of the team’s research have been published online in the 7 June edition of the Proceedings of the National Academy of Sciences.

Dr Karupiah’s work is supported by the Howard Hughes Medical Institute (USA), the National Health and Medical Research Council of Australia and the John Curtin School of Medical Research.