Progress Toward Human Gene Therapy

THE TECHNOLOGY of gene transfer has evolved over nearly 50 years since studies of DNA-mediated bacterial transformation reported by Avery et al in 1944.1These earliest gene transfer experiments explored "the chemical nature of the substance inducing transformation of pneumococcal types."1 More than two decades later, mammalian cells were transformed with SV40 and polyoma papovavirus DNA by calcium phosphate—mediated cellular uptake.2-4In 1971, the first workshop on gene therapy was held.5Recombinant DNA technology provided the first approaches for cell transfer of disease-related genes (ie, β-globin [hemoglobinopathies] and hypoxanthine guanine phosphoribosyltransferase [Lesch-Nyhan syndrome]).6-10The Human Genome Project, with its high rate of heritable disease and cancer gene discoveries, fuels the opportunities for gene transfer therapy. Replication-defective viral vectors are essential vehicles for gene transfer. Safe viral vectors were developed in the laboratories of Mulligan, Verma, Miller, and Gilboa based on the basic research on the life