ABSTRACT
Subtype G has been estimated to represent the fourth most prevalent clade in the HIV-1 pandemic and subtype F is widely circulating in parts of South America (frequently within BF recombinant forms) and in Romania. However, functional envelope clones of these subtypes are lacking, which are needed for studies on antibody-mediated neutralization, coreceptor usage, and efficiency of viral entry inhibitor drugs. Here we report the construction, neutralization properties, and coreceptor usage of HIV-1 functional envelope clones of subtypes G (n = 15) and F (n = 7). These clones were obtained through RT-PCR amplification of HIV-1 gp160 from plasma RNA, and were used for pseudovirus production. All 15 subtype G-enveloped pseudoviruses were resistant to neutralization by gp120-targeted broadly neutralizing monoclonal antibodies (MAbs) b12 and 2G12, while a majority were neutralized by gp41-targeted MAbs 2F5 and 4E10. With regard to the subtype F envelopes, all seven pseudoviruses were resistant to 2F5 and b12, six were resistant to G12, and six were neutralized by 4E10. Coreceptor usage testing revealed that 21 of 22 envelopes were CCR5-tropic, including all 15 subtype G envelopes, seven of which were from patients with CD4(+) T cell counts <200/ml. These results confirm the broadly neutralizing activity of 4E10 on envelope clones across all tested group M clades, including subtypes G and F, reveal the resistance of most subtype F-enveloped pseudoviruses to broadly neutralizing MAbs b12, 2G12, and 2F5, and suggest that, similarly to subtype C, CXCR4 tropism is uncommon in subtype G, even at advanced stages of infection.
Subject(s)
Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , CD4 Antigens/metabolism , HIV Antibodies/metabolism , HIV Envelope Protein gp160/metabolism , HIV Infections/metabolism , HIV-1/metabolism , Protein Engineering/methods , Amino Acid Sequence , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/pharmacology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/pharmacology , CD4 Antigens/immunology , Cell Line , Cloning, Molecular , HIV Antibodies/immunology , HIV Antibodies/pharmacology , HIV Envelope Protein gp120/chemistry , HIV Envelope Protein gp120/immunology , HIV Envelope Protein gp120/metabolism , HIV Envelope Protein gp160/chemistry , HIV Envelope Protein gp160/classification , HIV Envelope Protein gp160/immunology , HIV Envelope Protein gp41/chemistry , HIV Envelope Protein gp41/immunology , HIV Envelope Protein gp41/metabolism , HIV Infections/immunology , HIV Infections/virology , HIV-1/drug effects , HIV-1/immunology , Humans , Molecular Sequence Data , Molecular Typing , Neutralization Tests , Phylogeny , Plasmids , Protein Binding , Protein Structure, Tertiary , TransfectionABSTRACT
We report the identification of a new HIV-1 circulating recombinant form (CRF47_BF) derived from subtypes B and F. It was initially identified in protease-reverse transcriptase sequences from nine individuals from three separate regions of Spain who acquired HIV-1 infection via sexual contact. All nine sequences formed a strongly supported phylogenetic cluster, branching apart from all known CRFs, and in bootscan analyses were BF mosaics with two coincident breakpoints. Two epidemiologically unlinked viruses were sequenced in near full-length genomes, which exhibited identical mosaic structures, with 16 intersubtype breakpoints in a genome predominantly of subtype B. Subtype F segments of the new CRF failed to cluster with any of the near full-length genome subtype F sequences available in public databases. Recent dates of HIV-1 diagnoses and short genetic distances suggest a recent origin of this CRF. This is the tenth reported CRF_BF, the first apparently having originated outside of South America.
Subject(s)
HIV Infections/virology , HIV-1/classification , HIV-1/isolation & purification , Recombination, Genetic , Cluster Analysis , Female , Genome, Viral , Genotype , HIV Protease/genetics , HIV Reverse Transcriptase/genetics , HIV-1/genetics , Humans , Male , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA , SpainABSTRACT
We report the near full-length genome characterization of an HIV-1 subtype F virus (D88_845) collected in St. Petersburg, Russia, from a 25-year-old Russian woman perinatally infected in 1982. In a Bayesian phylogenetic analysis, the genome sequence branched basally to the subsubtype F1 clade. In partial sequences, D88_845 clustered with 13 other subtype F sequences from Russia, corresponding to gag (n = 2), pol (n = 3), and env (n = 8) segments. At least 11 of these sequences are from samples collected in St. Petersburg from heterosexually infected Russian individuals. In each of these segments, the Russian viruses formed a monophyletic cluster that branched as a sister clade of the F1 subsubtype. One sequence from Belgium branched with D88_845 with a posterior probability of 0.99. This is the first report on the identification and near full-length genome characterization of the subtype F variant circulating in St. Petersburg, which is closely related to, but distinct from, the F1 subsubtype.
