Example 3
To produce the modified antibody (vAb), expiCHO cells were transfected with a vector (pc 3.4-vAbL, pc 3.4-vAbH) containing the gene encoding the modified antibody (vAb) protein and cultured, and the modified antibody was purified using affinity chromatography. An XK16 column packed with the affinity resin MabSelect SuRe™ (GE Healthcare) was equilibrated by flushing with buffer A (25 mM Tris, pH 7.0, 25 mM NaCl), and then the culture was flushed and bound to the affinity resin, and the modified antibody (vAb) protein was eluted with buffer B (25 mM citric acid, pH 3.5). After completion of purification, the column was washed with 0.5 M NaOH, and then packed with 20% ethanol and cold-stored. The pH of the eluted sample was adjusted to 6.0 by adding a suitable amount of 1 M Tris (pH 9.0) thereto. The state of the sample was checked through 10% SDS-PAGE. The obtained modified antibody (vAb) protein was subjected to buffer exchange by dialysis against a buffer containing 10 mM sodium succinate and 30 mM sucrose (pH 6.0).
