A method of enriching a sample for amyloid ß peptides

Abstract

The invention relates to a method of enriching a sample for amyloid β peptides, comprising (i) contacting the sample with a solid support having thereon an immobilised anti-amyloid β peptide antibody;

Claims

1. A method of enriching a sample for amyloid p peptides, said method comprising(i) contacting the sample with a solid support having immobilised thereon an anti-amyloid p peptide antibody;(ii) washing said solid support with a washing solution which has a pH between 10.5 and 10.7;(iii) applying an elution solution which has a pH between 10.5 and 10.7 to said solid support; and(iv) collecting the eluted sample.

2. The method of claim 1, wherein the solid support is stirable and preferably comprises magnetisable particles, more preferably superparamagnetic beads.

3. The method of any preceding claim, wherein step (i) further comprises mixing the solid support and the sample.

4. The method of any preceding claim, wherein step (iii) further comprises mixing the elution solution and the sample.

5. The method of claim 4, wherein the elution solution and the solid support are mixed for 30 to 90 minutes, preferably for about 1 hour.

6. The method of any preceding claim, wherein in step (ii) the solid support and the washing solution are mixed for 5 to 15 minutes, preferably for about 10 minutes.

7. The method of claim 4 or claim 5, wherein mixing of the solid support and the elution solution is performed in a centrifuge at 800 to 1400 rpm, preferably 1000 to 1200 rpm, more preferably around 1100 rpm.

8. The method of any preceding claim, wherein prior to washing step (ii), the solid support is washed with a washing solution which has a pH between 9 and 10, optionally this further washing step is preceded by an additionalwashing step with a washing solution which has an approximately neutral pH.

9. The method of any preceding claim, wherein the washing solution in step (ii) and the elution solution in step (iii) have the same composition.

10. The method of any preceding claim, wherein the antibody is reactive to amino acid residues 1 to 16 of amyloid p.

11. The method of any preceding claim wherein the solid support is streptavidin coated and the antibody is biotinylated.

12. The method of any preceding claim, wherein the eluted sample is enriched for amyloid p 1-40 and / or 1-42 peptides.

13. The method of any preceding claim, wherein the sample is a plasma sample, preferably a human plasma sample.

14. A method of analysing amyloid p peptides in a sample comprising performing the enrichment method of claim 1 and then applying said eluted sample to a liquid chromatography column.

15. The method of claim 14, wherein the eluted sample is applied to the liquid chromatography column without changing the solution thereof, such that the sample applied to the liquid chromatography column has a pH between 10.5 and 10.7.

16. The method of claim 14 or claim 15, wherein the pH of the mobile phase used to perform the liquid chromatography is between 10.5 and 10.7.

17. The method of any preceding claim, wherein the pH of the washing solution, the elution solution and the mobile phase is 10.6.

18. The method of any one of claims 14 to 17, wherein one or more eluted fractions form the liquid chromatography column are analysed using a mass spectrometer.

19. The method of claim 18, wherein the liquid chromatography column is operably linked to said mass spectrometer.5 20. The method of any of claims 14 to 19, wherein an interior surface of theliquid chromatography column has an alkylsilyl coating.A

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