LONG-TERM PROTECTION AGAINST HIV-1 INFECTION CONFERRED BY TAT OR REV ANTISENSE RNA WAS AFFECTED BY THE DESIGN OF THE RETROVIRAL VECTOR

We have constructed a series of retroviral vectors in which the expres sion of antisense RNA targeted at the full length coding sequence of H IV-I tat or rev was driven by three different promoters and in the con text of double-copy or single-copy vectors. Jurkat cells transduced by these vectors were shown to express the expected tat or rev antisense RNA without alteration in cell proliferation or surface CD4 expressio n. After challenge with HIV, four patterns of protection were identifi ed, with the degree of protection being determined primarily by the de sign of the expression system. In those patterns showing long-term com plete protection, we could detect no HIV p24 in the culture supernatan ts or in the cells, and no HIV RNA or HIV proviral DNA (by PCR), durin g a 23-week follow-up. Experiments designed to rescue any live virus s till formed in the culture after 20 weeks' challenge demonstrated that , with some constructs, infectious virus could no longer be isolated, while with other constructs, only a low level of infectious virus was still being formed and providing a continuing virus challenge, althoug h all other markers of infection remained undetectable. Our results de monstrated that antisense RNA expression driven by tRNA promoter in th e context of a double-copy vector conferred better long-term protectio n against HIV infection compared to that driven by HIV LTR or MLV LTR promoters, and that the optimized vectors may be useful in developing a gene therapy against HIV-I infection and AIDS. (C) 1996 Academic Pre ss. Inc.