SYDNEY - Researchers at the Cooperative Research Centre (CRC) for Vaccine Technology are working on ways to adapt a technique discovered recently by Australian scientists that greatly improves the effectiveness of DNA vaccines.

Jeff Boyle, who pioneered the technique, revealed in a paper in the March issue of the journal Nature, now is working at the CRC for Vaccine Technology, in Melbourne, and with the CRC's joint owner, the biotechnology-pharmaceutical company CSL Ltd., to boost the effect of DNA vaccines.

Boyle told BioWorld International diseases that are the subject of research by the CRC, including rheumatic fever and malaria, would be considered for treatment with the improved DNA vaccines.

DNA vaccines are, in effect, harmless versions of a real pathogen that hijack cells by inserting their own genome in the cells and using the cell machinery to make copies of themselves. As a result, they provoke an immune response much closer to that of the real invader than traditional vaccines, but without causing trouble to the host body.

DNA vaccines constructed to date have worked well for systems with a small number of cells, but have a very weak result for larger organisms.

The contribution by Boyle and coworkers at the Walter and Eliza Hall Institute, in Melbourne, where Boyle worked on the technique as part of a doctoral thesis, was to marry a DNA virus to a molecule that attached to a receptor on a target cell.

Specifically, Boyle linked the vaccine to the molecule known as CTLA4, which links to the receptor known as B7 on the target molecule in the test mice.

Boyle said there was a 10,000-fold improvement in the effect of the DNA vaccine early in the treatment. *