Lab Canada

New phase of testing on prions starting at NRC

Quebec City, QC – April 27, 2004 – TSO3, a company that develops sterilization solutions, says it is undertaking a third phase of testing in collaboration with the National Research Council of Canada (NRC) in Winnipeg. The testing is part of the company’s research program on prions, the infectious proteins that cause Creutzfeldt-Jakob Disease, the human version of mad cow disease.

The aim of this third phase of testing is to confirm the capacity of its 125L ozone sterilizer to deactivate the strains of prions. The experiments are being carried out on transgenic mice from the laboratory of Dr Stanley Prusiner (a 1997 Nobel Prize winner for his research on prions). This species of transgenic mouse is the animal most sensitive to prions. The protocol utilized compares ozone sterilization to the usual steam sterilization, and to a steam cycle that is much hotter which is considered as the only option available that could reduce some of the risk of prions, without guaranteeing the total disappearance of infectiousness.

“The best scenario would be that all the animals inoculated from ozone-sterilized plaques are still alive on the 180th day and present no signs of the disease, and that those inoculated from plaques sterilized in an autoclave are sick," says Simon Robitaille, vice president, operations, and director of research at TSO3. "This result would show that ozone is more effective than the steam that is currently recommended for sterilizing prions for lack of a more effective solution.”

It has been shown that Creutzfeldt-Jakob Disease can be transmitted by surgical instruments, while no sterilization method currently in use can deactivate the infectious prions that cause the disease. In 2001, TSO3 undertook a research program to validate the effectiveness of its sterilization process with reference to prions. The first step consisted of validating the effectiveness of ozone with a yeast protein that is a twin of the prion, with very positive results. In 2002, the second phase of testing carried out on real prions (in vitro) at the NRC in Winnipeg, with financial and technical assistance from the Industrial Research Assistance Program (NRC- IRAP) showed the potential of the 125L ozone sterilizer when it was impossible to detect the presence of prions with the methods available, after only a quarter of the standard sterilization cycle.

TSO3 says it has since met with key figures in the international scientific community to obtain a consensus regarding the protocol to utilize for the subsequent phase, which will eventually allow the company to submit requests to the regulatory authorities of the countries concerned for the commercial phase.

The company also says it had been waiting since the fall of 2003 for the transgenic mice required for the testing. These mice are particularly sensitive to manipulations and the producers had to cope with challenges to the stability of the genes inserted into the genome of the mice from previous models.

The experiments consist of taking the brains from sick mice and making a homogenate that is spread on plaques to dry and then sterilized in the ozone sterilizer while other samples are sterilized with steam, in order to compare the effectiveness of the ozone sterilizer to the autoclave. Next, the residual prions are recovered from the plaques and then injected into the brains of the test mice. This third phase of testing is expected to take six months.

If the results are conclusive, the following step will be to inoculate mice with strain of BSE prions that are the direct cause of mad cow disease in cattle, and the variant that causes Creutzfeldt-Jakob Disease (vCJD) in humans. TSO3 intends to complete this research in England with the help of a surgical model utilizing implants in materials analogous to surgical instruments, but this time over a 365-day period.

In parallel, the development of a biological prion indicator will also get underway with a non-infectious yeast protein called SUP-35, whose physical- chemical properties allow it to take the shape of a prion and react like one. This protein will be utilized by TSO3 in the development of a prion indicator to monitor prion deactivation, in the form of a small, throwaway measurement device designed to confirm repeatedly and reliably whether a sterilization and prion deactivation cycle has been successfully achieved.

On September 9, 2002, TSO3 announced the signing of a licensing contract with the Universit de Montral and Polyvalor that gave TSO3 the right to exploit the patents related to the invention of a biological prion indicator based on the SUP-35 yeast.