HIV-1 dual/mixed tropic isolates show different genetic and phenotypic characteristics and response to maraviroc in vitro

• Published in: Antiviral research 2011-04, Vol.90 (1), p.42-53
• Main Authors: Svicher, Valentina, Balestra, Emanuela, Cento, Valeria, Sarmati, Loredana, Dori, Luca, Vandenbroucke, Ina, D’Arrigo, Roberta, Buonomini, Anna Rita, Van Marck, Herwig, Surdo, Matteo, Saccomandi, Patrizia, Mostmans, Wendy, Aerssens, Jeroen, Aquaro, Stefano, Stuyver, Lieven J., Andreoni, Massimo, Ceccherini-Silberstein, Francesca, Perno, Carlo Federico
• Format: Article
• Language: English
• Subjects: Anti-HIV Agents - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiviral agents; Biological and medical sciences; Cell Line; Cyclohexanes - pharmacology; Env mutations; Fundamental and applied biological sciences. Psychology; Genetics; High-Throughput Nucleotide Sequencing; HIV Envelope Protein gp120 - genetics; HIV Envelope Protein gp41 - genetics; HIV Infections - virology; HIV-1 - drug effects; HIV-1 - genetics; HIV-1 - growth & development; HIV-1 - physiology; HIV-1 tropism; Human immunodeficiency virus 1; Humans; Maraviroc; Medical sciences; Microbiology; Molecular Sequence Data; Pharmacology. Drug treatments; Phenotyping; Pyrosequencing; Receptors, Virus - metabolism; Triazoles - pharmacology; Viral Tropism; Virology; Virus Attachment; Virus Replication - drug effects
• ISSN: 0166-3542; 1872-9096
• DOI: 10.1016/j.antiviral.2011.02.005

Dual/mixed-tropic HIV-1 strains are predominant in a significative proportion of patients, though few information is available regarding the genetic characteristics, quasispecies composition, and susceptibility against CCR5-antagonists of the primary-isolates. For this reason, we investigated in deep details, both phenotypically and genotypically, the characteristics of 54 HIV-1 primary-isolates obtained from HIV-infected patients. Tropism was assessed by multiple-cycles phenotypic-assay on U87MG-CD4 +-CCR5 +-/CXCR4 +-expressing cells. In vitro selection in PBMCs of X4-tropic viral strains following maraviroc-treatment was also performed. Phenotypic-assay reported pure R5-tropic viruses in 31 (57.4%) isolates, dual/mixed-tropic viruses in 22 (40.7%), and pure X4-tropic virus in only 1 (1.8%). Among dual/mixed-tropic isolates, 12 showed a remarkably higher replication-efficacy in CCR5-expressing cells (R5 +/X4), and 2 in CXCR4-expressing cells (R5/X4 +). Genotypic-tropism testing showed a correlation between PSSM-scores, geno2pheno false-positive-rate, and V3-net-charge with both CCR5-usage and syncytium-inducing ability. Moreover, specific gp120- and gp41-mutations were significantly associated with tropism and/or syncytium-inducing ability. Ultra-deep V3-pyrosequencing showed the presence of a swarm of genetically distinct species with a preference for CCR5-coreceptor not only in all pure R5-isolates, but also in 6/7 R5 +/X4-tropic isolates. In both pure-X4 and R5/X4 +-isolates, we observed extensive prevalence of X4-using species. In vitro selection-experiments with CCR5-inhibitor maraviroc (up to 2 months) showed no-emergence of X4-tropic variants for all R5- and R5 +/X4-isolates tested (while X4-virus remained fully-resistant). In conclusion, our study shows that dual/mixed-tropic viruses are constituted by different species, whereby those with characteristics R5 +/X4 are genotypically and phenotypically similar to the pure-R5 isolates; thus the use of CCR5-antagonists in patients with R5 +/X4-tropic viruses may be a therapeutic-option that deserves further investigations.