title: Activity of non-nucleoside reverse transcriptase inhibitors against HIV-2 and SIV.
abstract: BACKGROUND
  After the initial discovery of 1-(2-hydroxyethoxymethyl)-6-(phenylthio)thymine (HEPT) and tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-one and thione (TIBO) derivatives, several other non-nucleoside reverse transcriptase (RT) inhibitors (NNRTI), including nevirapine (BI-RG-587), pyridinone derivatives (L-696,229 and L-697,661), delavirdine (U-90152), alpha-anilinophenylacetamides (alpha-APA) and various other classes of NNRTI have been described. The hallmark of NNRTI has been based on their ability to interact with a specific site ('pocket') of HIV-1 RT.
  
  
  OBJECTIVE
  To investigate whether, in addition to HIV-1, different strains of HIV-2 (ROD and EHO) and SIV (mac251, agm3 and mndGB1) are sensitive to a selection of NNRTI i.e. delavirdine, the HEPT derivative I-EBU (MKC-442), 8-chloro-TIBO (tivirapine), alpha-APA (loviride), nevirapine and the pyridinone derivative L-697,661.
  
  
  RESULTS
  The NNRTI tested inhibited the replication of the different strains of HIV-2 and SIV at micromolar concentrations. The inhibitory effects of the NNRTI on HIV-2-induced cytopathicity correlated well with their inhibitory effects on HIV-2 RT activity. Drug-resistant HIV-2 (EHO) variants containing the Ser102Leu and/or Glu219Asp mutations in their RT were selected after passaging the virus in MT-4 cells in the presence of increasing concentrations of delavirdine. The EHO virus mutants were at least 20-fold less susceptible to the antiviral effects of delavirdine. Some cross-resistance, depending on the mutant strain, was observed with the other NNRTI tested (i.e. MKC-442, tivirapine, loviride and pyridinone L-697,661).
  
  
  CONCLUSIONS
  Our data demonstrate that NNRTI are not exclusively specific for HIV-1 but are also inhibitory to different HIV-2 and SIV strains. These observations will have important implications for the development of new NNRTI with higher activity against both HIV-1 and HIV-2. Furthermore, in view of their anti-SIV activity, NNRTI could be evaluated further for their in vivo anti-retrovirus efficacy in non-human primate models.
authors.affiliation: Rega Institute for Medical Research, Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Witvrouw
authors.forename: C
authors.initials: C
authors.lastname: Pannecouque
authors.forename: K
authors.initials: K
authors.lastname: Van Laethem
authors.forename: J
authors.initials: J
authors.lastname: Desmyter
authors.forename: E
authors.initials: E
authors.lastname: De Clercq
authors.forename: A M
authors.initials: AM
authors.lastname: Vandamme
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000494:pharmacology*; D002478:Cells, Cultured / Q000821:virology; D003588:Cytopathogenic Effect, Viral; D020008:Delavirdine / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D054303:HIV Reverse Transcriptase / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects / Q000502:physiology; D015498:HIV-2 / Q000187:drug effects* / Q000502:physiology; D008969:Molecular Sequence Data; D012194:RNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D015302:Simian Immunodeficiency Virus / Q000187:drug effects* / Q000502:physiology
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors; D020008:Delavirdine; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase