Additive and antagonist effects of therapeutic gene combinations for suppression of HIV-1 infection

Antiviral Res. 2002 Jul;55(1):77-90. doi: 10.1016/s0166-3542(02)00009-8.


A previously described Moloney-based vector expressing a double copy anti-tat antisense tRNA (DC-tRNA-AT) (Biasolo et al., 1996. J. Virol. 70, 2154-2161) was modified to increase the copy number of the antisense molecule and to target the intra-cytoplasmic localization of the HIV genome. To this end, an anti-U5 hammerhead ribozyme, engineered as a hybrid small adenoviral VAI RNA (VAIalpha), was inserted into the vector as a single molecule or in combination with the double copy anti-tat sequence. The retroviral vector expressing only VAIalpha (DC-VAIalpha) inhibited HIV-1 replication to an extent comparable to that of DC-tRNA-AT. A more effective inhibition was produced by the vector expressing multiple copies of the anti-tat antisense (DC-6tRNA-AT). This higher effectiveness correlated with anti-tat stochiometry, i.e. with the absolute number of therapeutic molecules being produced on a per cell basis at the steady state. Surprisingly, when the tRNA-AT and VAIalpha genes were combined in the same vector (DC-AT-VAIalpha), an enhancement of viral replication was noticed. This study indicates that it is possible to potentiate the antiviral activity of a retroviral vector by increasing the steady-state level of the therapeutic molecule. Results also show that the combined expression of two singularly active therapeutic RNAs can have antagonistic rather than synergistic effects.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Gene Products, tat / genetics
  • Genetic Therapy*
  • Genetic Vectors*
  • HIV-1* / physiology
  • Humans
  • Jurkat Cells
  • RNA, Antisense / chemistry
  • RNA, Antisense / genetics
  • RNA, Catalytic / genetics
  • Retroviridae / genetics
  • Statistics as Topic
  • Transfection
  • Virus Replication
  • tat Gene Products, Human Immunodeficiency Virus


  • Gene Products, tat
  • RNA, Antisense
  • RNA, Catalytic
  • hammerhead ribozyme
  • ribozyme UV5
  • tat Gene Products, Human Immunodeficiency Virus