Products and Method for the Decontamination of Prions

Abstract

The invention relates to the use of Cu and the derivatives thereof, for the decontamination of prions, especially for decontaminating medical devices or medical surgical devices at risk, for decontaminating work surfaces, and for decontaminating any potentially infectious compound.

Description

EXAMPLE 1

Prion Decontamination Solution Containing CuSO₄ and H₂O₂

a) Study of the action of copper associated with H₂O₂ on the degradation of the PrP^sc present in infectious brain homogenates of mice.

Solutions of CuSO₄ and of H₂O₂ at different concentrations are added to samples consisting of infectious extracts of murine brain homogenates and are left in contact for about 30 mins at ambient temperature.

The samples are then deposited on a polyacrylamide SDS-PAGE gel after adjustment of the protein concentrations and digestion with proteinase K (PK) at a concentration of 1 mg of PK per 50 mg of protein. The presence of PrP^sc is revealed by Western blotting.

The results obtained are illustrated by FIG. 1. It can be seen that at a concentration of 100 μM of CuSO₄ and 50 mM of H₂O₂, the infectious samples display decreased levels of PrP^sc. At a concentration of 500 μM of CuSO₄ and 50 mM of H₂O₂, the level of PrP^sc present in the infectious homogenates becomes undetectable in Western blotting (tracks 7 and 8). At this concentration, the effect is potentiated by the action of H₂O₂.

With the use of higher doses of CuSO₄ from 1 mM to 10 mM, the PrP^sc signal can be made to disappear with copper alone and H₂O₂ is no longer necessary.

These results are confirmed on repeating these experiments on homogenates deriving from the brains of mice infected with the 22 L prion strain. Similar results have been obtained on homogenates deriving from the murine Chandler strain and BSE, which shows that the decontaminating effect is not strain-dependent.

b) Study of the infectivity of infectious brain homogenates treated with a high concentration of copper in vitro.

22 L brain homogenates were treated for about 30 mins with different concentrations of CuSO₄ with and without H₂O₂ at different concentrations.

These homogenates are dialyzed, then deposited onto cells of murine neuroblastomas having the capacity to replicate the infectious agent.

Untreated brain homogenates are used as the control.

A Western blot is performed after 6 passages on the cell lysates and after digestion with PK, in order to test for the presence of PrP^sc signifying that the samples tested still remain infectious.

The results obtained are given in FIG. 2. It can be seen that the infection is decreased by the treatment.

EXAMPLE 2

Tests In Vivo

A confirmation of these results observed in vitro has been effected. Infectious 22 L brain homogenates were treated in particular with 500 μM of CuSO₄ and 100 mM of H₂O₂. The homogenates, treated or untreated, were inoculated into mice by the intracerebral route. The control animals inoculated with the untreated homogenates all fell ill in 168 days±2 days. Certain animals inoculated with the treated homogenates are still alive after more than 300 days. This result demonstrates that a reduction of at least 7 powers of ten in the infectious titer can be obtained by this decontamination method.

EXAMPLE 3

Decontamination of Surgical Equipment

Equipment such as endoscopes is immersed in a solution containing 1 mg of CuSO₄ for 20 mins. The tests performed to identify the presence of prions after this treatment were found to be negative.

EXAMPLE 4

Study of the Efficacy of Decontamination

The data concerning the efficacy of decontamination tested in vivo after inoculation into the mouse are given below. For this, control and decontaminated brain homogenates were intracerebrally inoculated into the mouse (C57B1).

The survival times of the mice are as follows:

1) Inoculation of control infectious homogenates: 167.6±0.5 days.

2) Homogenates treated with CuSO₄ (0.5 mM, 30 mins, ambient temperature): 200.2±8.9 days.

3) Homogenates treated with CuSO₄ (1 mM, 30 mins, ambient temperature): 217.2±13.4 days.

4) Homogenates treated with CuSO₄ (1 mM)+H₂O₂ (100 mM, 30 mins, ambient temperature): 266.4±15.6 days.

In the light of these incubation periods under these different conditions and a titration curve for the infectious agent effected on these mice, it can be estimated that the decontamination obtained is greater than 10⁴ in the homogenates treated just with CuSO₄ and greater than 10⁵ in the homogenate treated with CuSO₄+H₂O₂.

Claims

1. The use of derivatives of Cu and of its derivatives for the prion decontamination of infected products and equipment.

2. The use as claimed in claim 1, characterized in that these derivatives are used with H2O2.

3. The use as claimed in claim 1, characterized in that the metal derivative is CuSO4.

4. The use as claimed in claim 1, characterized in that the compound or compounds used are in the form of aqueous solutions.

5. A method for decontamination of products or equipment infected with pathogenic agents responsible for prion diseases, characterized in that it comprises placing them in contact with at least one compound such as defined in claim 1, or a solution containing it, and if necessary also with H2O2.

6. The method as claimed in claim 5, characterized in that the metal derivative is CuSO4.

7. The method as claimed in claim 5, characterized in that the decontamination treatment is carried out with a solution containing said compound at a level of at least 500 μM, in particular from 500 to 1000 μM.

8. The method as claimed in claim 5, characterized in that H2O2 is present in the solutions at a level of about 50 mM.

9. An application of the method as claimed in claim 5 for the decontamination of medical or medical-surgical devices at risk, such as multiple use equipment, such as endoscopes, or also decontamination of work surfaces, such as a draining board or floor.

10. The application of the method as claimed in claim 5 for the decontamination of any potentially infectious compound and in particular animal meal or other contaminated products of animal origin.