title: Inhibition of dual/mixed tropic HIV-1 isolates by CCR5-inhibitors in primary lymphocytes and macrophages.
abstract: BACKGROUND
  Dual/mixed-tropic HIV-1 strains are predominant in a significant proportion of patients, though little information is available regarding their replication-capacity and susceptibility against CCR5-antagonists in-vitro. The aim of the study was to analyze the replication-capacity and susceptibility to maraviroc of HIV-1 clinical isolates with different tropism characteristics in primary monocyte-derived-macrophages (MDM), peripheral-blood-mononuclear-cells (PBMC), and CD4(+) T-lymphocytes.
  
  
  METHODS
  Twenty-three HIV-1 isolates were phenotipically and genotipically characterized as R5, X4 or dual (discriminated as R5(+)/X4, R5/X4, R5/X4(+)). Phenotypic-tropism was evaluated by multiple-cycles-assay on U87MG-CD4(+)-CCR5(+)-/CXCR4(+)-expressing cells. Genotypic-tropism prediction was obtained using Geno2Pheno-algorithm (false-positive-rate [FPR] = 10%). Replication-capacity and susceptibility to maraviroc were investigated in human-primary MDM, PBMC and CD4(+) T-cells. AMD3100 was used as CXCR4-inhibitor. Infectivity of R5/Dual/X4-viruses in presence/absence of maraviroc was assessed also by total HIV-DNA, quantified by real-time polymerase-chain-reaction.
  
  
  RESULTS
  Among 23 HIV-1 clinical isolates, phenotypic-tropism-assay distinguished 4, 17 and 2 viruses with R5-tropic, dual/mixed-, and X4-tropic characteristics, respectively. Overall, viruses defined as R5(+)/X4-tropic were found with the highest prevalence (10/23, 43.5%). The majority of isolates efficiently replicated in both PBMC and CD4(+) T-cells, regardless of their tropism, while MDM mainly sustained replication of R5- or R5(+)/X4-tropic isolates; strong correlation between viral-replication and genotypic-FPR-values was observed in MDM (rho = 0.710;p-value = 1.4e-4). In all primary cells, maraviroc inhibited viral-replication of isolates not only with pure R5- but also with dual/mixed tropism (mainly R5(+)/X4 and, to a lesser extent R5/X4 and R5/X4(+)). Finally, no main differences by comparing the total HIV-DNA with the p24-production in presence/absence of maraviroc were found.
  
  
  CONCLUSIONS
  Maraviroc is effective in-vitro against viruses with dual-characteristics in both MDM and lymphocytes, despite the potential X4-mediated escape. This suggests that the concept of HIV-entry through one of the two coreceptors "separately" may require revision, and that the use of CCR5-antagonists in patients with dual/mixed-tropic viruses may be a therapeutic-option that deserves further investigations in different clinical settings.
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Surdo
authors.forename: Emanuela
authors.initials: E
authors.lastname: Balestra
authors.forename: Patrizia
authors.initials: P
authors.lastname: Saccomandi
authors.forename: Fabiola
authors.initials: F
authors.lastname: Di Santo
authors.forename: Marco
authors.initials: M
authors.lastname: Montano
authors.forename: Domenico
authors.initials: D
authors.lastname: Di Carlo
authors.forename: Loredana
authors.initials: L
authors.lastname: Sarmati
authors.forename: Stefano
authors.initials: S
authors.lastname: Aquaro
authors.forename: Massimo
authors.initials: M
authors.lastname: Andreoni
authors.forename: Valentina
authors.initials: V
authors.lastname: Svicher
authors.forename: Carlo Federico
authors.initials: CF
authors.lastname: Perno
authors.forename: Francesca
authors.initials: F
authors.lastname: Ceccherini-Silberstein
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D065100:CCR5 Receptor Antagonists; D002460:Cell Line; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D005838:Genotype; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000821:virology; D008214:Lymphocytes / Q000187:drug effects / Q000821:virology*; D008264:Macrophages / Q000187:drug effects / Q000821:virology*; D010641:Phenotype; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors; D056189:Viral Tropism; D014779:Virus Replication / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D065100:CCR5 Receptor Antagonists; D019718:Receptors, CXCR4