Method for the purification of a non-immunoglobulin protein comprising an immunoglobulin-like (Ig-like) domain

1. A method for purifying or capturing a non-immunoglobulin protein of interest having between one and ten immunoglobulin-like (Ig-like) domains from a biological fluid, comprising the steps of:

a) contacting the biological fluid containing the protein of interest with a Hydrophobic Charge Induction Chromatography (HCIC) resin, wherein the HCIC resin comprises a mercapto-ethyl pyridine ligand,

b) washing out the resin with a buffer to remove unbound contaminants, and

c) eluting the protein of interest by treating the resin with a buffer solution comprising an organic solvent, wherein the organic solvent is isopropyl alcohol, propylene glycol and/or polyalcohols.

2. The method according to claims 1 , wherein the organic solvent used in step c) is propylene glycol.

3. The method according to claim 2 , wherein the concentration of propylene glycol in the solution is between about 25 and 50%.

4. The method according to claim 1 , wherein step a) is carried out at acidic pH.

5. The method according to claim 4 , wherein the pH used is between about 3 and 6.8.

6. The method according to claim 1 , wherein the washing of step b) is carried out with a buffer solution having an acidic pH.

7. The method according to claim 6 , wherein the pH used is between about 3 and 6.8.

8. The method according to claim 1 , wherein the biological fluid is selected from a cell-conditioned culture medium, cell lysate, cell extract, tissue extract, blood plasma, serum, milk, urine, ascites, cerebrospinal fluid, vegetable juice, plant extracts or a fraction obtained from an earlier chromatographic separation step.

9. The method according to claim 1 , wherein the protein of interest has 1 to 7 Ig-like domains.

10. The method according to claim 1 , wherein the protein of interest is selected from IL- 18 binding protein (IL-18BP), NCAM, Fibronectin type III, ICAM- 1, mad CAM-1, PE CAM-1, VCAM-1, titin, cadherin, neurocan, LIFR, CNTFR, IL-1R, IL-3R, IL5R, IL-6R, IL-12R, GM-CSFR, oncostatin M receptor (OSMR), VEGF receptor, FGF receptor, hPDGF receptor, T cell receptor, MHC proteins, microglobulin-β, CTLA4, B7 molecule, neuregulin, coagulation factor XIII, NF-κB, IL6-IL6R, beta-galactosidase and superoxide dismutase or an isoform, mutein, fused protein, or fragment thereof comprising at least one Ig-like domain.

11. The method according to claim 10 , wherein the protein is IL-18BP.

12. The method according to claim 1 , wherein the purification factor of the eluted protein is in the range of 11 and 94 fold.

13. The method according to claim 12 , wherein the purification factor of the eluted protein is 94 fold.

14. The method according to claim 1 , wherein the concentration factor of the eluted protein is in the range of 1.5 and 3.1 fold.

15. The method according to claim 14 , wherein the concentration factor of the eluted protein is 3.1 fold.

16. The method according to claim 1 , wherein the yield of the eluted protein is in the range of 73 and 98%.

17. The method according to claim 16 , wherein the yield of the eluted protein is about 85%.

18. The method according to claim 1 , wherein the purification factor of the eluted protein is in about 94 fold.