RETROVIRAL GENE-TRANSFER AND SUSTAINED EXPRESSION OF HUMAN ARYLSULFATASE-A

Transduction of mouse hematopoietic stem cells and their progeny was s tudied using a recombinant retroviral vector (MFG-ASA) which incorpora tes the human arylsulfatase A gene (ASA;EC3.1.6.8). Successful transdu ction was demonstrated in spleen colonies of mice that received bone m arrow transplantation, cultured bone marrow-derived macrophages, visce ral tissues and brain of long-term reconstituted mice, and also the sp leen colonies of secondarily transplanted mice. The efficiency of tran sduction in primary spleen colonies was 95%. Expression of the ASA tra nsgene exceeded endogenous levels in spleen colonies and in cultured m acrophages by 50-100%. Enzyme activity in the visceral tissues of long -term reconstituted mice consistently showed elevated ASA activity, gr eater than three-fold in the spleen and lung of one animal. Increased activity of ASA also could be detected in secondary spleen colonies. t hese data demonstrate the usefulness of the MFG-ASA vector for efficie nt gene transfer and expression in mouse hematopoietic stem cells and their differentiated progeny. The presence of vector DNA in the brain 4 months after transplantation suggests a role for gene transfer and s tem cell transplantation in the treatment strategies for metachromatic leukodystrophy.