Preparation and composition of inter-alpha proteins from blood

1. A method for purifying inter-alpha inhibitor proteins (IαIp proteins), wherein the IαIp proteins comprise inter-alpha inhibitor (IαI) comprising two heavy chains (H1 and H2) and a light chain (L) and pre-alpha inhibitor (PαI) comprising a heavy chain (H3) and a light chain (L), and wherein the method comprises a wash step wherein the IαIp proteins bound to a chromatography support are exposed to a wash buffer having a pH of about 4.0 or lower, wherein the wash step results in a loss of 20% or less of the IαIp proteins from the support.

2. The method of claim 1 , wherein the pH of the wash buffer is about 3.6 or lower.

3. The method of claim 2 , wherein the pH of the wash buffer is about 3.3 or lower.

4. The method of claim 3 , wherein the pH of the wash buffer is between about 3.3 and to about 2.9.

5. The method of claim 1 , wherein the support is compatible with liquid chromatography, column chromatography, anion-exchange chromatography, or a combination thereof.

6. The method of claim 5 , wherein the support is a monolithic support or particle-based support.

7. The method of claim 6 , wherein the monolithic support or particle support comprises an immobilized anion-exchange ligand.

8. The method of claim 7 , wherein the immobilized anion-exchange ligand is a diethylaminoethane (DEAF) or a quaternary amine (Q).

9. The method of claim 1 , further comprising, prior to said wash step, exposing the support to a wash buffer having a salt concentration of about 250 mM NaCl or higher.

10. The method of claim 1 , wherein the IαIp proteins are purified from blood.

11. The method of claim 1 , wherein the IαIp proteins are purified from blood plasma or a blood plasma fraction.

12. The method of claim 11 , wherein the blood plasma is cryo-poor plasma or the blood plasma fraction is an intermediate plasma fraction.

13. The method of claim 12 , wherein the intermediate plasma fraction is an IαIp containing fraction.

14. The method of claim 10 , wherein the blood is from a human, primate, bovine, equine, porcine, ovine, feline, canine, or combinations thereof.

15. The method of claim 1 , wherein the IαIp proteins have an apparent molecular weight of between about 60 to about 280 kDa.

16. The method of claim 1 , wherein the IαIp proteins have biological activity.

17. The method of claim 16 , wherein the biological activity is a cytokine inhibitor activity, chemokine inhibitor activity, or a serine protease inhibitor activity.

18. The method of claim 1 , further comprising a viral inactivation step or nanofiltration step.

19. The method of claim 18 , wherein the viral inactivation step or nanofiltration step occurs before the chromatography step.

20. The method of claim 18 , wherein the viral inactivation step or nanofiltration step occurs after the chromatography step.

21. A method for purifying inter-alpha inhibitor proteins (IαIp protein proteins), wherein the IαIp proteins comprise inter-alpha inhibitor (IαI) comprising two heavy chains (H1 and H2) and a light chain (L) and pre-alpha inhibitor (PαI) comprising a heavy chain (H3) and a light chain (L), the method comprising:

a) placing blood, a blood plasma fraction, or an intermediate plasma fraction on a chromatography support, and

b) subjecting the support to a wash buffer with a pH of about 4.0 or lower, wherein the wash step results in a loss of 20% or less of the IαIp proteins from the support.

22. The method of claim 21 , wherein the IαIp proteins bind to the support.