SYDNEY - The Cooperative Research Centre for Vaccine Technology, in Brisbane, has achieved good results in trials with mice for a vaccine engineered to react to all forms of the virus that causes rheumatic fever and acute tonsillitis.

In addition, in a separate project looking for a vaccine for malaria, the center has developed a safe method of deliberately injecting patients with the malaria parasite, then monitoring the progress of the disease using a sensitive DNA test as a means of directly evaluating the effect of proposed vaccines. The patients are cured with well-tried countermeasures before they show any symptoms of malaria.

Major companies have shown interest in the advances in both projects, revealed in a talk given to a seminar in Sydney by Michael Good, director of the Centre for Vaccine Technology, which is associated with the Queensland Institute of Medical Research at the Royal Brisbane Hospital.

At the seminar, one of a regular series organized by the Centre for Science Communication at the University of Technology, in Sydney, Good said his team identified a small segment of coat protein found on all strains of the Group A Streptococcus organism.

Concentrating initially on a vaccine for rheumatic disease, the center developed the technology necessary to fold that small segment of protein in such a way as to increase its effect on the immune system and so increase the system's ability to fight the disease.

In preliminary experiments the center immunized mice with the folded protein segment and showed they were effectively protected from rheumatic disease.

Good told BioWorld International the center is now testing suitable adjuvants, which are immunostimulants designed to increase the effect of the protein segments on the immune system.

Success in those studies will lead to the vaccine being tested in people in the Phase I and Phase II trials conducted by a company set up by the center, called Vaccine Solutions Pty Ltd.

Good said the facilities for Phase I and Phase II trials of new vaccines and bioproducts are very limited in Australia, but he also observed that enough drugs are now being developed in Australia to keep the new Vaccine Solutions facilities occupied.

The development of a vaccine for rheumatic fever is at present more for the public benefit than of commercial interest. The disease, which affects the heart and shortens life span, is an emerging one among Australia's aborigines.

However, Good noted the research would have direct application to the more commercial but less serious diseases of acute tonsillitis and skin sores.

The second project being conducted at the center is much further away from identifying any useful vaccine for malaria - a disease for which there is no vaccine and which is becoming more resistant to long-standing treatment methods.

Assay Developed, Blood Supply Made

However, center researcher Allan Saul said major pharmaceutical and biotech companies have shown strong interest in the techniques used to directly monitor the effect vaccines have on the parasite.

He said one breakthrough in developing the technique was creation of a very sensitive assay for parasites in blood - achieved by PCR amplification of DNA from a patient's blood sample, then testing for the DNA of the malaria parasite.

The assay was sufficiently sensitive to detect parasite concentrations of 10 parasites per milliliter of blood. Microscopic checks can only detect concentrations of 20,000 parasites per milliliter, but patients show clinical symptoms of the disease when parasite concentrations reach 10,000 to 20,000 parasites per milliliter of blood.

The second breakthrough was to develop a supply of blood infected with parasites they knew they could defeat with existing cures, but which was otherwise completely clean.

That supply of blood was created by sending several volunteer patients already infected with malaria to the University of Edinburgh, in Scotland, which had the facilities to take blood from the patients and create the supply.

The trial involves deliberately injecting patients with infected blood, then using the sensitive assay to see how the parasites develop and determine whether their progress is affected by a test vaccine. The infection is then stopped before it causes symptoms. *

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