Abstract
A8 virus (A8-V) is a molecular clone of the neuropathogenic FrC6 virus derived from the Friend murine leukemia virus (F-MuLV). The A8-V infects endothelia and microglia in the brain. We constructed a gene transfer system with the A8-V gene. Pseudotyped virus carrying the surface protein of A8-V (A8-SU) transduced the β-glactosidase gene incorporated in the retroviral vector efficiently to cultured microglial cells derived from newborn rats. Ex vivo gene transferred microglial cells were then injected into the right hemi-sphere of 3-day-old and 3-week-old rat brains. All of the rats examined at 4 weeks after the injection contained the labeled microglial cells in the brain (7/7 and 5/5 of the rats injected at 3 days and 3 weeks, respectively). None of the rats showed pathological changes in the whole body investigated, including the central nervous system, 4 weeks after transplantation of the labeled microglial cells.