Disclosed is a method for producing a host cell protein-reduced (HCP-reduced) anti-IL-13 antibody, or antigen-binding portion thereof, preparation from a sample mixture comprising an anti-IL-13 antibody, or antigen-binding portion thereof, and at least one HCP, said method comprising: (a) contacting said sample mixture with Protein A affinity chromatography resin, washing said affinity chromatography resin with a buffer comprising 25 mM Tris, 100 mM NaCl, pH 7.2, followed by a buffer comprising 20 mM sodium citrate/citric acid, 0.5 M NaCl, pH 6.0, and then with a buffer comprising 25 mM Tris, 100 mM NaCl, pH 7.2, and collecting an affinity chromatography sample (b) subjecting said affinity chromatography sample to a reduction in pH thus forming a reduced pH sample, wherein reduced pH sample has a pH of about 3 to about 4 (c) adjusting said reduced pH sample to a pH of about 4.5 to about 8.5 and contacting said adjusted pH sample to an anion exchange material and collecting an ion exchange sample (d) contacting said ion exchange sample to a hydrophobic interaction chromatography (HIC) material and collecting an HIC sample, wherein said HIC sample comprises said HCP-reduced antibody, or antigen-binding portion thereof, preparation.
