Lentiviral triplex DNA, and vectors and recombinant cells containing DNA triple helix lentiviral.

Expression vector HIV-1 comprising: a) a purified or isolated comprising at least one copy of acting regions cPPT and CTS cis a retrovirus nucleic acid, wherein said regions cPPT and CTS induce structure three stranded DNA and b) a heterologous nucleic acid sequence, wherein the HIV-1 LTR is deleted for the promoter and enhancer of U3.