Purpose Of Review: HIV-1 enters CD4-expressing cells via one or both of the chemokine receptors CCR5 and CXCR4. Specific CCR5 antagonists are now in clinical use, but only for CCR5-tropic viruses. Hence, several methods have been developed for assessing HIV-1 tropism in patients who are candidates for CCR5 antagonists. This article reviews current data on phenotypic assays of tropism.
Recent Findings: Phenotypic assays are still used as reference, although genotypic methods have improved. The main advantages of phenotypic assays are their great sensitivity for detecting minor CXCR4-using variants and their capacity to assess non-B subtypes of HIV-1. Clinical trials of maraviroc have, thus, relied on the phenotypic determination of HIV-1 tropism. However, new genotypic approaches that are more sensitive for minor CXCR4-using variants, notably ultra-deep pyrosequencing, are now challenging phenotypic assays. Nevertheless, phenotypic assays are essential for improving genotypic algorithms for determining HIV-1 tropism as well as for assessing the resistance of R5-tropic viruses to CCR5 antagonists.
Summary: HIV-1 tropism should be determined before using CCR5 antagonists. Phenotypic recombinant assays are still the benchmark tests for characterizing HIV-1 tropism as their great sensitivity enables them to detect minor CXCR4-using variants of both B and non-B HIV-1 subtypes.
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http://dx.doi.org/10.1097/COH.0b013e328356f6d7 | DOI Listing |
The tropism of the Human Immunodeficiency Virus type 1 (HIV-1) is determined by the use of either or both of the chemokine coreceptors CCR5 (R5) or CXCR4 (X4) for entry into the target cell. The ability of HIV-1 to bind R5 or X4 is determined primarily by the third variable loop (V3) of the viral envelope glycoprotein gp120. HIV-1 strains of pandemic group M contain an antisense gene termed , which overlaps outside the region encoding the V3 loop.
View Article and Find Full Text PDFViruses
November 2024
Departments of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
HIV-1 subtype C viruses are responsible for 50% of global HIV burden. However, nearly all currently available reporter viruses widely used in HIV research are based on subtype B. We constructed and characterized a replication-competent HIV-1 subtype C reporter virus expressing mGreenLantern.
View Article and Find Full Text PDFCurr HIV Res
January 2025
Clinical Laboratory, The People's Hospital of Baoding, Baoding, Hebei, 071000, China.
Virology
January 2025
Research Group Medical Biotechnology & Bioengineering, Faculty of Applied Natural Sciences, TH Köln - University of Applied Sciences, Campusplatz 1, 51379, Leverkusen, Germany. Electronic address:
In the past three decades, human immunodeficiency virus type 1 (HIV-1)-derived vectors were evolved and became indispensable to transduce therapeutic genes into a range of different target cell types to facilitate a variety of gene therapeutic strategies. To achieve this, i) the biosafety profile of the vectors was incrementally enhanced and ii) the CD4-restricted tropism mediated by the envelope proteins (Env) of the parental virus needed to be directed towards recruitment of other receptors expressed on the desired target cells. Here, a closer look is first taken at the development of vector components and the mechanisms of Env incorporation into particles.
View Article and Find Full Text PDFJ Infect Dis
November 2024
INSERM UMR1291-CNRS UMR5051-Université Toulouse III, Toulouse Institute for Infectious and Inflammatory Diseases F-31300, France.
Background: The persistence of latently infected cells prevents a cure of HIV. The intestinal mucosa contains numerous target cells, and high levels of HIV-1 DNA persist in this compartment under ART. While CD4+ T cells are the best characterized reservoir of HIV-1, the role of long-lived intestinal macrophages in HIV-1 persistence on ART remains controversial.
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