A NONPRODUCER, INTERFERING HUMAN-IMMUNODEFICIENCY-VIRUS (HIV) TYPE-1 PROVIRUS CAN BE TRANSDUCED THROUGH A MURINE LEUKEMIA VIRUS-BASED RETROVIRAL VECTOR - RECOVERY OF AN ANTI-HIV MOUSE-HUMAN PSEUDOTYPE RETROVIRUS

The expression of a human immunodeficiency virus (HIV) type 1 provirus (F12-HIV) cloned from a nonproducer, chronically infected CD4 down-re gulated Hut-78 cell clone (F12) does not lead to the formation of vira l particles and, upon transfection in HeLa CD4(+) cells, confers resis tance to HIV superinfection without affecting the CD4 receptor exposur e. In an attempt to transfer the anti-HIV properties of F12-HIV into h uman primary cells, we constructed a Moloney murine leukemia virus-bas ed retroviral vector containing an F12-HIV genome lacking the 3' long terminal repeat and part of the nef gene, which was expressed under th e control of its 5' long terminal repeat. The F12-HIV genome was inser ted in the orientation opposite to that of the murine leukemia virus t ranscriptional unit and was designated the N2/F12-HIV nef- antisense v ector. Lymphoblastoid CEMss cells, as well as human peripheral blood l ymphocytes, were successfully transduced by the recombinant retrovirus emerging from the producer PA317 clones. CEMss clones expressing the F12-HIV nef- antisense vector became resistant to HIV superinfection e ven at the highest utilized multiplicity of infection (10(5) 50% tissu e culture infective doses per 10(6) cells). In transduced CEMss cells the viral interference induced by the F12-HIV expression is not due to CD4 HIV receptor down-regulation. Nonproducer, interfering HIV provir uses transduced into retroviral vectors may, therefore, provide an alt ernative strategy for the protection of CD4(+) human primary cells fro m HIV infection, which strategy may be used in designating a safe and efficient gene therapy protocol for patients with AIDS.