New vaccine concept applied to HIV vaccine

6 May 1999

in 1999

Australian Breakthrough promises vaccines for ‘difficult’ diseases

Scientists all over the world have been battling with the problem of HIVvaccines for almost a decade. But now, a new “polytope” technology from the CRC for Vaccine Technology is being applied to HIV and many other diseases..

A new approach to vaccination developed by the CRC for Vaccine Technology has widespread implications for the prevention and treatment of ‘difficult’ diseases such as melanoma, glandular fever and HIV/AIDS. The new patented “polytope” vaccine strategy has been successfully tested in mice.

“An experimental HIV polytope vaccine has recently been tested in mice and in the test tube using cells from HIV infected patients,” said PhD student Tonia Woodberry. Tonia has been working on this project for one and a half years, based in Brisbane at the Queensland Institute of Medical Research. At ScienceNOW! she presented the work in public for the first time.

Vaccines are one of the most cost-effective methods of protecting the public against infectious disease, but traditional vaccine strategies are limited for some diseases. Now, this discovery allows scientists to consider designing another generation of medical and veterinary vaccines, which stimulate a different kind of immune response.

Traditional vaccines against for example tetanus and measles work by inducing antibodies. Unfortunately, antibodies may be of little value in protecting people against melanoma, glandular fever and HIV/AIDS. Research suggests that vaccines against these diseases would probably need to activate a different arm of the immune system – white blood cells known as killer T cells.

“But inducing killer T cells against HIV has proven difficult because HIV has a habit of constantly mutating and changing – so a vaccine which generates good killer T cells to one form of the virus, quickly becomes redundant as the virus changes and escapes immune detection and destruction,” said Tonia Woodberry.

Scientists at the CRC for Vaccine Technology have argued that for an HIV vaccine to work, the vaccine should induce killer T cells capable of killing all the different mutated forms of HIV. To acheive this aim they have developed this new polytope technology which combines many different bits of HIV in a single vaccine. “This is a real breakthrough because it means that one day, we might be able to provide a single vaccine that can offer protection against many different forms of HIV,” said Tonia Woodberry.

“In the past, most vaccines used whole protein, but they’re after an antibody response. Here we are using only the bit that the killer T cell recognises, nothing else. And what is different about our approach is that we’ve managed to string them together, end to end, all in one line. They are very tiny, between seven and nine amino acids each, and yet they are all recognised – our experiments show that in mice as well as in blood samples taken from patients with HIV, the HIV polytope vaccine induces multiple killer T cells. If the virus mutates we have already the trained immune system to recognise a potential mutant,” said Tonia Woodberry.

“Results are encouraging, but a number of scientific hurdles remain before this concept can be tested in humans. On average the development of a vaccine takes 10 years or more with many failing along the way,” said Tonia Woodberry.

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