Easy-to-make vaccine tackles a range of illnesses

Australian researchers have created a totally synthetic vaccine that is effective against viruses, harmful bacteria and tumours and could lead to a powerful new arsenal of vaccines for humans and animals.

Lead researcher, Associate Professor David Jackson, from the University of Melbourne’s Department of Microbiology and Immunology and the Cooperative Research Centre for Vaccine Technology (CRC-VT), says the striking biological effectiveness of these totally synthetic and easy-to-assemble vaccines makes them highly attractive for future development.

“Synthetic vaccines offer several advantages over traditional vaccines. For example, unlike traditional vaccines which contain small quantities of live or attenuated viruses, the synthetic vaccines don’t include any infectious material.

“Also, they can be produced economically on a large scale and there is no risk of genetic mix-ups, which is a problem facing regulatory authorities dealing with DNA vaccination.”

Associate Professor Jackson is a Principal Research Fellow with the National Health and Medical Research Council of Australia and the Chief Scientist at VacTX Pty Ltd, a company established by EQiTX Limited and the CRC-VT in January 2004 to commercialise the synthetic peptide technology.

The unique structure of the vaccine that Associate Professor Jackson and his colleagues have created means that it can be designed to target specific types of immune reactions. For example in one form it will trigger antibodies, in another it triggers a cell-mediated immune response.

Associate Professor Jackson says that other researchers have previously attempted to design similar peptide-based vaccines but have been largely unsuccessful because they are too weak to generate a significant response and depend on additional support from drugs or natural substances to boost their action.

“To overcome this problem we added a lipid structure to our vaccine. Lipid structures are known to be powerful boosters to immune responses, so essentially we equipped our vaccine with its own internal boosting mechanism,” he says.

“The vaccine is based on a very simple design composed of two epitopes – the short sequences of proteins that are recognised by the immune system and trigger responses in the body – and a lipid structure that acts to target the vaccine to a particular cell in the body, the dendritic cell. In doing so, it amplifies the resulting immune response enormously.”

Associate Professor Jackson says that while the lipid component specifically targets the vaccine to the dendritic cell, one of the epitopes targets immune helper cells. The second epitope is designed to trigger the antibody or cellular immune response (the nature of the second epitope determines which) and makes its way to the surface of the host cell. Once here it triggers the immune response.

The research, which was recently published in the Proceedings of the National Academy of Sciences, is the result of collaboration between scientists at the Cooperative Research Centre for Vaccine Technology in the University of Melbourne’s Department of Microbiology and Immunology and the Queensland Institute of Medical Research.