HIGH EXPRESSION OF A B-DOMAIN DELETED FACTOR-VIII GENE IN A HUMAN HEPATIC CELL-LINE

The expression of a modified human coagulation factor VIII cDNA in a h uman liver-derived cell line is described. A B-domain deleted FVIII (r VIIIdB928) cDNA controlled by a strong viral promoter/enhancer was lin ked to a dominant selection-/amplification marker and transfected into the human hepatic cell line SK-HEP-I. By means of this system, up to 3.5 U rFVIIIdB928/10(6) cells x 24 h could be detected immediately aft er selection without gene amplification. This level is orders of magni tude higher than that obtained in Chinese hamster ovary (CHO) cells un der the same conditions. Efficient expression of rFVIIIdB928 in SK-HEP -1 cells was temperature dependent, a 4-fold higher level of activity was achieved in culture supernatants at decreased incubation temperatu res of 28 degrees C. This system allows the production of high amounts of recombinant rFVIIIdB928 without time and labour consuming gene amp lification procedures. (C) 1998 Elsevier Science B.V. All rights reser ved.