Cell isolation method
The present invention relates to a method of isolating cells from a sample which method comprises binding said cells to a solid support by means of a non-specific ligand immobilised on said solid support, particularly to a method of isolating microorganisms from a sample. Preferred ligands for use in such methods include carbohydrates and derivatives thereof. Also described is a kit for isolating microorganisms from a sample comprising: (a) a solid support having immobilised thereon a ligand which is capable of non-specific binding to microorganisms; (b) means for binding microorganisms to said solid support; optionally (c) means for lysing said cells; and optionally (d) means for binding nucleic acid released from said lysed cells to a solid support.
1. A method of isolating cells from a sample which method comprises (a) binding said cells to a magnetic solid support by means of a non-specific ligand covalently attached to said solid support wherein said ligand is a polysaccharide comprising at least one of mannose, galactose and a derivative of mannose or galactose and wherein the cells bind to the saccharide moieties of said ligand; and (b) separating the solid support with the cells bound thereto from the remainder of the sample.
2. A method as claimed in claim 1 wherein the cells are microorganisms.
3. A method as claimed in claim 2 wherein the microorganisms are bacteria.
4. A method as claimed in claim 3 wherein representatives from at least 30% of the different bacterial species present in the sample are bound to said solid support.
5. A method as claimed in claim 3 wherein representatives from at least 60% of the different bacterial species present in the sample are bound to said solid support.
6. A method as claimed in claim 1 wherein the ligand is a nutrient.
7. A method as claimed in claim 1 wherein the ligand is selected from the group consisting of Gum, guar, carrageenan and mannan.
8. A method as claimed in claim 1 wherein the solid support is particulate.
9. A method as claimed in claim 1 which additionally comprises a step of identifying one or more of the cells bound to said solid support.
10. A method as claimed in claim 9 wherein the cells are identified using a cell type specific nucleic acid probe.
11. A method as claimed in claim 9 wherein the bound cells are lysed to release their nucleic acid.
12. A method as claimed in claim 11 wherein the released nucleic acid is bound to a solid support.
13. A method of detecting a microorganism in a sample, said method comprising:
(a) binding said microorganism to a magnetic solid support by means of a non-specific ligand covalently attached to said solid support wherein said ligand is a polysaccharide comprising at least one of mannose, galactose and a derivative of mannose or galactose and wherein the cells bind to the saccharide moieties of said ligand;
(b) separating the solid support with the cells bound thereto from the remainder of the sample; and
(c) identifying the microorganism bound to said solid support.
14. A method as claimed in claim 13 wherein step (c) comprises lysing the microorganisms.
15. A method as claimed in claim 14 wherein the nucleic acid released from said lysed microorganisms is bound to a solid support.
16. The method as claimed in claim 1 wherein the derivative is selected from the group consisting of aldonic acid, uronic acid, deoxy, amino, sulfated and alcohol derivatives of galactose and mannose.
17. The method as claimed in claim 13 wherein the derivative is selected from the group consisting of aldonic acid, uronic acid, deoxy, amino, sulfated and alcohol derivatives of galactose and mannose.
18. The method as claimed in claim 1 wherein said ligand comprises 13 or more covalently linked monosaccharide units.
19. The method as claimed in claim 13 wherein said ligand comprises 13 or more covalently linked monosaccharide units.
20. A method as claimed in claim 1 wherein the ligand comprises mannose.