METABOLIC CORRECTION AND CROSS-CORRECTION OF MUCOPOLYSACCHARIDOSIS TYPE-II (HUNTER SYNDROME) BY RETROVIRAL-MEDIATED GENE-TRANSFER AND EXPRESSION OF HUMAN IDURONATE-2-SULFATASE

To explore the possibility of using gene transfer to provide iduronate -2-sulfatase (IDS; EC 3.1.6.13) enzyme activity for treatment of Hunte r syndrome, an amphotropic retroviral vector, L2SN, containing the hum an IDS coding sequence was constructed and studied for gene expression in vitro. Lymphoblastoid cell lines (LCLs) from patients with Hunter syndrome were transduced with L2SN and expressed high levels of IDS en zyme activity, 10- to 70-fold higher than normal human peripheral bloo d leukocytes or LCLs. Such L2SN-transduced LCLs failed to show accumul ation of (SO4)-S-35 into glycosaminoglycan ((SO4-GAG)-S-35), indicatin g that recombinant IDS enzyme participated in GAG metabolism. Cocultur e of L2SN-transduced LCLs with fibroblasts from patients with Hunter s yndrome reduced the accumulation of (SO4-GAG)-S-35. These results demo nstrated retroviral-mediated IDS gene transfer into lymphoid cells and the ability of such cells to provide recombinant enzyme for intercell ular metabolic cross-correction.