RESTORATION OF HEXOSAMINIDASE-A ACTIVITY IN HUMAN TAY-SACHS FIBROBLASTS VIA ADENOVIRAL VECTOR-MEDIATED GENE-TRANSFER

Tay-Sachs disease (TSD) is a lysosomal storage disease due to hexosami nidase A deficiency caused by mutations in the gene for alpha-chain (H ex alpha). A human Hex alpha cDNA was subcloned into the adenoviral pl asmid pAdRSV.Hex alpha. Replication-deficient adenovirus was generated by homologous recombination in 293 cells. Human fibroblasts from a pa tient suffering from TSD were infected with the recombinant adenovirus . TSD fibroblasts expressing the recombinant alpha-chain had an enzyme activity on the natural substrate ranging from 40 to 84% of the norma l. The corrected cells secreted up to 25 times more Hex alpha than con trol fibroblasts. The Hex alpha encoded by the adenovirus was shown to be correctly transported into the lysosomes and to normalize the impa ired degradation of GM2 ganglioside in TSD fibroblasts.