ABSTRACT
Viral isolates from 27 HIV-1-infected patients in Ghana, most of whom were symptomatic, were characterized for coreceptor usage using MT-2 and U87.CD4 cells. Irrespective of clinical status, most infections were caused by CCR5-tropic viruses although three CXCR4-tropic viruses were also found. Genotyping was performed by sequencing the gp41 region. Seven viruses clustered with subtype G reference strains, while the remaining 20 viruses clustered within the subtype A reference viruses. Most subtype A isolates clustered loosely with the CRF02_AG viruses and are described as CRF02_AG-like. The V3 loop was sequenced in selected isolates including all isolates capable of using CXCR4. The V3 region of CXCR4-using viruses contained genetic traits characteristic of CXCR4-using subtype B and C viruses, such as increased charge, the presence of positively charged residues at positions 11 and 25, and loss of a predicted glycosylation site. This study supports previous work showing that CRF02_AG is responsible for most HIV-1 infections in Ghana at this time. The predominance of CCR5-using viruses, even in symptomatic patients, suggests that CCR5-blocking strategies may be useful for prevention and treatment of HIV-1 infections in Ghana.
Subject(s)
HIV Infections/virology , HIV-1/metabolism , Phenotype , Adult , Base Sequence , CD4 Lymphocyte Count , Cell Line , Female , Ghana , HIV Envelope Protein gp41/chemistry , HIV Envelope Protein gp41/genetics , HIV-1/classification , HIV-1/genetics , HIV-1/isolation & purification , Humans , Infant , Male , Middle Aged , Molecular Sequence Data , Phylogeny , Receptors, CCR5/metabolism , Receptors, CXCR4/metabolism , Retrospective Studies , Sequence Analysis, DNAABSTRACT
Tuberculosis (TB) is the major opportunistic infection of HIV-infected patients in developing countries and is associated with activation of the immune system and increased HIV-1 expression. The aim of this study was to explore the biological properties of HIV-1 isolates from patients with active TB. Ten HIV-1 subtype C isolates were analyzed for biological phenotypes, using MT-2 cells, and for coreceptor usage, using coreceptor-transfected cell lines. All isolates were nonsyncytium inducing (NSI) in the MT-2 assay and replicated in CCR5-expressing cells. None of the isolates used CXCR4 or any of the minor coreceptors (CCR1, CCR2b, or CCR3) efficiently. Analysis of the V3 region showed that all isolates contained the GPGQ motif characteristic of subtype C and also had a sequence profile typical of NSI viruses. These data indicate that despite their advanced disease state, patients with TB harbor viruses that use the CCR5 coreceptor. It is possible that activation of monocytes and macrophages during TB infection results in the expansion of macrophage-tropic isolates that preferentially use CCR5.
Subject(s)
AIDS-Related Opportunistic Infections/virology , HIV Infections/virology , HIV-1/metabolism , Receptors, CCR5/metabolism , Tuberculosis/virology , AIDS-Related Opportunistic Infections/complications , Acute Disease , Amino Acid Sequence , Cell Line , Giant Cells , HIV Envelope Protein gp120/genetics , HIV Infections/complications , HIV-1/genetics , Humans , Molecular Sequence Data , Peptide Fragments/genetics , Receptors, HIV/metabolism , Sequence Alignment , Tuberculosis/complications , Virus ReplicationABSTRACT
CCR5 serves as a requisite fusion coreceptor for clinically relevant strains of human immunodeficiency virus type 1 (HIV-1) and provides a promising target for antiviral therapy. However, no study to date has examined whether monoclonal antibodies, small molecules, or other nonchemokine agents possess broad-spectrum activity against the major genetic subtypes of HIV-1. PRO 140 (PA14) is an anti-CCR5 monoclonal antibody that potently inhibits HIV-1 entry at concentrations that do not affect CCR5's chemokine receptor activity. In this study, PRO 140 was tested against a panel of primary HIV-1 isolates selected for their genotypic and geographic diversity. In quantitative assays of viral infectivity, PRO 140 was compared with RANTES, a natural CCR5 ligand that can inhibit HIV-1 entry by receptor downregulation as well as receptor blockade. Despite their divergent mechanisms of action and binding epitopes on CCR5, low nanomolar concentrations of both PRO 140 and RANTES inhibited infection of primary peripheral blood mononuclear cells (PBMC) by all CCR5-using (R5) viruses tested. This is consistent with there being a highly restricted pattern of CCR5 usage by R5 viruses. In addition, a panel of 25 subtype C South African R5 viruses were broadly inhibited by PRO 140, RANTES, and TAK-779, although approximately 30-fold-higher concentrations of the last compound were required. Interestingly, significant inhibition of a dualtropic subtype C virus was also observed. Whereas PRO 140 potently inhibited HIV-1 replication in both PBMC and primary macrophages, RANTES exhibited limited antiviral activity in macrophage cultures. Thus CCR5-targeting agents such as PRO 140 can demonstrate potent and genetic-subtype-independent anti-HIV-1 activity.
