AMPHOTROPIC AND ECOTROPIC RETROVIRAL VECTOR VIRUSES TRANSDUCE MIDGESTATIONAL MURINE FETAL LIVER-CELLS IN A DUAL-CHAMBERED COCULTIVATION SYSTEM

A beta-glucuronidase cDNA was transferred into fetal liver cells (FLC) from mice affected with mucopolysaccharidosis (MPS) type VII and norm al littermates using a retrovirus vector. The cells were transduced by direct cocultivation or by culturing the FLC and vector packaging cel ls separated by a 0.45 mu m filter in a dual-chambered cocultivation s ystem. Gene transduction occurred using an ecotropic or amphotropic ve ctor in FLC obtained from 13.5- and 15.5-murine day-old murine fetuses . Histochemical staining assays and measurement of enzyme activity dem onstrated gene expression in the midgestational FLC. Enzyme secreted i nto the supernatant from transduced FLC obtained from 13.5-day-old aff ected fetuses surpassed secreted enzyme from normal, age-matched untra nsduced FLC. The 13.5 day FLC, transduced by direct cocultivation or b y using the dual-chambered system, were transplanted in utero into 13. 5-day-old murine fetuses. Proviral sequences were detected in various organs shortly after birth. The results indicate that midgestational F LC can be transduced with an amphotropic vector virus in a dual-chambe red cocultivation system without contaminating virus-producing packagi ng cells and that the transduced cells survive in utero transplantatio n.