Summary
This study examines the suitability of four recently characterised monoclonal antibodies (MAbs) for the immunoaffinity purification of human coagulation factor IX (FIX) from plasma concentrates. Initial studies using 125I-FIX indicated that appreciable amounts of bound FIX could be eluted from immobilised MAbs with 0.2 M glycine, 50% ethanediol pH 10 (buffer N). Further studies with FIX concentrates showed that buffer N eluted FIX without compromising the activity of the zymogen. Although FIX was eluted from all four MAbs with this buffer, the best yield (82%) was obtained with MAb ESN-3. ESN-3 bound 40 to 60 iu FIX per mg MAb when immobilised on Sepharose 4B. After washing, column elution with buffer N yielded FIX at 100-200 iu/mg. The purity of the product was confirmed by sodium-dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and by Western blotting. The product contained no detectable mouse IgG (<3%) and <1% FII, X, or protein C.
Keywords
Factor IX - Monoclonal antibodies - Immunopurification
