title: Identification of determinants on a dualtropic human immunodeficiency virus type 1 envelope glycoprotein that confer usage of CXCR4.
abstract: The chemokine receptors CCR5 and CXCR4, in combination with CD4, mediate cellular entry of macrophage-tropic (M-tropic) and T-cell-tropic strains of human immunodeficiency virus type 1 (HIV-1), respectively, while dualtropic viruses can use either receptor. We have constructed a panel of chimeric viruses and envelope glycoproteins in which various domains of the dualtropic HIV-1(DH12) gp160 were introduced into the genetic background of an M-tropic HIV-1 isolate, HIV-1(AD8). These constructs were employed in cell fusion and virus infectivity assays using peripheral blood mononuclear cells, MT4 T cells, primary monocyte-derived macrophages, or HOS-CD4 cell lines, expressing various chemokine receptors, to assess the contributions of different gp120 subdomains in coreceptor usage and cellular tropism. As expected, the dualtropic HIV-1(DH12) gp120 utilized either CCR3, CCR5, or CXCR4, whereas HIV-1(AD8) gp120 was able to use only CCR3 or CCR5. We found that either the V1/V2 or the V3 region of HIV-1(DH12) gp120 individually conferred on HIV-1(AD8) the ability to use CXCR4, while the combination of both the V1/V2 and V3 regions increased the efficiency of CXCR4 use. In addition, while the V4 or the V5 region of HIV-1(DH12) gp120 failed to confer the capacity to utilize CXCR4 on HIV-1(AD8), these regions were required in conjunction with regions V1 to V3 of HIV-1(DH12) gp120 for efficient utilization of CXCR4. Comparison of virus infectivity analyses with various cell types and cell fusion assays revealed assay-dependent discrepancies and indicated that events occurring at the cell surface during infection are complex and cannot always be predicted by any one assay.
authors.affiliation: Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0460, USA. MCho@nih.gov
authors.forename: M W
authors.initials: MW
authors.lastname: Cho
authors.forename: M K
authors.initials: MK
authors.lastname: Lee
authors.forename: M C
authors.initials: MC
authors.lastname: Carney
authors.forename: J F
authors.initials: JF
authors.lastname: Berson
authors.forename: R W
authors.initials: RW
authors.lastname: Doms
authors.forename: M A
authors.initials: MA
authors.lastname: Martin
mesh_terms: D000818:Animals; D001665:Binding Sites; D015704:CD4 Antigens / Q000378:metabolism; D002460:Cell Line; D002461:Cell Line, Transformed; D054407:Chemokine CCL4; D018946:Chemokine CCL5 / Q000378:metabolism; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000378:metabolism*; D019302:HIV Envelope Protein gp160 / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism; D019402:Macrophage Inflammatory Proteins / Q000378:metabolism; D008264:Macrophages / Q000821:virology; D008561:Membrane Fusion; D016865:Reassortant Viruses / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D054397:Receptors, CCR3; D019713:Receptors, CCR5 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism*; D019707:Receptors, Chemokine / Q000378:metabolism; D013601:T-Lymphocytes / Q000821:virology
chemical_list: C515350:CCR3 protein, human; D015704:CD4 Antigens; D054407:Chemokine CCL4; D018946:Chemokine CCL5; D015699:HIV Envelope Protein gp120; D019302:HIV Envelope Protein gp160; D019402:Macrophage Inflammatory Proteins; D054397:Receptors, CCR3; D019713:Receptors, CCR5; D019718:Receptors, CXCR4; D019707:Receptors, Chemokine