REPLICATION-COMPETENT CHIMERIC LENTI-ONCOVIRUS WITH EXPANDED HOST-CELL TROPISM

Baboon bone marrow was grafted into human immunodeficiency virus type 1-infected patients in the course of recent trials for AIDS treatment, Since the baboon genome harbors multiple copies of an endogenous onco virus, chimeric lenti-oncoviruses could emerge in the xenotransplant r ecipient, To analyze the potential replication competence of hybrid vi ruses between different genera of retroviruses, we replaced most of th e env gene of simian immunodeficiency, viruses with the env gene of an amphotropic murine leukemia virus. The hybrid virus could be propagat ed in human T-cell lines, in peripheral blood mononuclear cells of rhe sus macaques, and in CD4(-) B-cell lines, Because of the expanded cell tropism the hybrid virus might have a selective advantage in comparis on to parental viruses, Therefore, emerging chimeric viruses may be co nsidered a serious risk of xenotransplantation, A note of caution is a lso suggested for the use of pseudotyped lentiviral vectors for human gene therapy.