Chromatogram (top), SDS-PAGE (bottom left), and corresponding Western blot (bottom right) analyses for the purification of Fab D1.3 from culture broth (21-h culture) on a HiTrap SP Sepharose XL column. Sodium acetate (15 mM, pH 5.0) was employed for equilibration and the post wash. Elution was achieved by 20 mM MES, 4.5 mM sodium MES, 1.5 M NaCl (pH 5.5). Lane 1 load, 2 post wash, 3–9 elution fractions, M molecular weight markers