title: Role of the first and third extracellular domains of CXCR-4 in human immunodeficiency virus coreceptor activity.
abstract: The CXCR-4 chemokine receptor and CD4 behave as coreceptors for cell line-adapted human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) and for dual-tropic HIV strains, which also use the CCR-5 coreceptor. The cell line-adapted HIV-1 strains LAI and NDK and the dual-tropic HIV-2 strain ROD were able to infect CD4+ cells expressing human CXCR-4, while only LAI was able to infect cells expressing the rat homolog of CXCR-4. This strain selectivity was addressed by using human-rat CXCR-4 chimeras. All chimeras tested mediated LAI infection, but only those containing the third extracellular domain (e3) of human CXCR-4 mediated NDK and ROD infection. The e3 domain might be required for the functional interaction of NDK and ROD, but not LAI, with CXCR-4. Alternatively, LAI might also interact with e3 but in a different way. Monoclonal antibody 12G5, raised against human CXCR-4, did not stain cells expressing rat CXCR-4. Chimeric human-rat CXCR-4 allowed us to map the 12G5 epitope in the e3 domain. The ability of 12G5 to neutralize infection by certain HIV-1 and HIV-2 strains is also consistent with the role of e3 in the coreceptor activity of CXCR-4. The deletion of most of the amino-terminal extracellular domain (e1) abolished the coreceptor activity of human CXCR-4 for ROD and NDK but not for LAI. These results indicate that HIV strains have different requirements for their interaction with CXCR-4. They also suggest differences in the interaction of dual-tropic HIV with CCR-5 and CXCR-4.
authors.affiliation: INSERM U.332, Institute Cochin de Génétique Moléculaire, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Brelot
authors.forename: N
authors.initials: N
authors.lastname: Heveker
authors.forename: O
authors.initials: O
authors.lastname: Pleskoff
authors.forename: N
authors.initials: N
authors.lastname: Sol
authors.forename: M
authors.initials: M
authors.lastname: Alizon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D018604:Epitope Mapping; D005110:Extracellular Space; D015699:HIV Envelope Protein gp120 / Q000378:metabolism; D015658:HIV Infections / Q000503:physiopathology; D015497:HIV-1 / Q000254:growth & development*; D015498:HIV-2 / Q000254:growth & development; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D051381:Rats; D019718:Receptors, CXCR4; D015728:Receptors, HIV / Q000737:chemistry* / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
chemical_list: D000911:Antibodies, Monoclonal; D015699:HIV Envelope Protein gp120; D008565:Membrane Proteins; D019718:Receptors, CXCR4; D015728:Receptors, HIV; D011993:Recombinant Fusion Proteins