SDS-PAGE analysis following purification of partially purified Fab D1.3 on HiTrap protein G. Fractions (3–9) from chromatography on HiTrap SP Sepharose XL column (Fig. 1) were pooled and desalted on PD10 columns prior to loading into a HiTrap protein G column. Lane 1 PD10 desalted load, 2 flow through, 3 post wash, 4 and 5 eluate 1 and 2, respectively, M molecular weight markers