title: Inhibition of HIV-1 replication in macrophages by a heterodinucleotide of lamivudine and tenofovir.
abstract: OBJECTIVE
  (i) To generate a new heterodinucleotide (3TCpPMPA) comprising the drugs lamivudine and tenofovir which have been shown to act synergistically and (ii) to protect macrophages from 'de novo' HIV-1-infection through its administration.
  
  
  METHODS
  3TCpPMPA was obtained by coupling the morpholidate derivative of tenofovir with the mono n-tri-butylammonium salt of lamivudine 5'-monophosphate. Stability and metabolism were evaluated in vitro and in vivo in mice. 3TCpPMPA was encapsulated into autologous erythrocytes by a procedure of hypotonic dialysis, isotonic resealing and reannealing. 3TCpPMPA-loaded erythrocytes were modified to increase their phagocytosis by human macrophages. Macrophages were infected by HIV-1(Ba-L) and inhibition of HIV-1 replication was assessed by HIV p24(gag) quantification.
  
  
  RESULTS
  Pharmacokinetic studies in mice revealed a rapid disappearance of the heterodinucleotide from circulation (t(1/2)=15 min) without any advantage compared with the administration of single drugs. Adding free 3TCpPMPA to macrophages (18 h), a 90% inhibition of viral replication up to 35 days post-treatment was achieved, while only a 60% inhibition was obtained by the combined treatment 3TC and (R)PMPA. When 3TCpPMPA was selectively targeted to the macrophage compartment by a single addition of loaded erythrocytes, the protection of macrophages from 'de novo' infection (99% protection 3 weeks post-treatment) was nearly complete.
  
  
  CONCLUSIONS
  Erythrocytes loaded with 3TCpPMPA and modified to increase their phagocytosis are able to protect macrophages from 'de novo' HIV-1 infection. 3TCpPMPA acts as an efficient antiviral pro-drug that, once inside macrophages, can be slowly converted into 3TCMP and (R)PMPA protecting these cells for a longer period of time.
authors.affiliation: Institute of Biochemistry G. Fornaini, University of Urbino Carlo Bo, 61029 Urbino, Italy. l.rossi@uniurb.it
authors.forename: Luigia
authors.initials: L
authors.lastname: Rossi
authors.forename: Palmarisa
authors.initials: P
authors.lastname: Franchetti
authors.forename: Francesca
authors.initials: F
authors.lastname: Pierigé
authors.forename: Loredana
authors.initials: L
authors.lastname: Cappellacci
authors.forename: Sonja
authors.initials: S
authors.lastname: Serafini
authors.forename: Emanuela
authors.initials: E
authors.lastname: Balestra
authors.forename: Carlo-Federico
authors.initials: CF
authors.lastname: Perno
authors.forename: Mario
authors.initials: M
authors.lastname: Grifantini
authors.forename: Raffaele
authors.initials: R
authors.lastname: Caliò
authors.forename: Mauro
authors.initials: M
authors.lastname: Magnani
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D000818:Animals; D019380:Anti-HIV Agents / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D019259:Lamivudine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology*; D008264:Macrophages / Q000821:virology*; D051379:Mice; D063065:Organophosphonates / Q000493:pharmacokinetics / Q000494:pharmacology*; D018894:Reverse Transcriptase Inhibitors / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D000068698:Tenofovir; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D019380:Anti-HIV Agents; D003470:Culture Media; D007202:Indicators and Reagents; D063065:Organophosphonates; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D000068698:Tenofovir; D000225:Adenine