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Functional characteristics of HIV-1 subtype C compatible with increased heterosexual transmissibility

DOI: 10.1097/QAD.0b013e32832a1806 DOI Help
PMID: 19390419 PMID Help

Authors: Brandon Walter (Laboratory of Persistent Viral Diseases, National Institutes of Health, USA) , Andy Armitage (MRC Human Immunology Unit, University of Oxford.) , Stephen Graham (University of Cambridge) , Tulio De Oliveira (University of the Western Cape) , Peter Skinhøj (Department of Infectious Diseases, Rigshospitalet, Denmark) , E. Yvonne Jones (Wellcome Trust Centre for Human Genetics) , David I. Stuart (Wellcome Trust Centre for Human Genetics) , Andre J. Mcmichael (MRC Human Immunology Unit, University of Oxford) , Bruce Chesebro (Laboratory of Persistent Viral Diseases, National Institutes of Health, USA) , Astrid K. N. Iversen (MRC Human Immunology Unit, University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Aids , VOL 23 (9) , PAGES 1047-1057

State: Published (Approved)
Published: February 2009

Abstract: Background: Despite the existence of over 50 subtypes and circulating recombinant forms of HIV-1, Subtype C dominates the heterosexual pandemic causing approximately 56% of all infections.Objective: To evaluate whether viral genetic factors may contribute to the observed subtype-C predominance.Methods: Chimeric viruses were generated using V1-V3 envelope fragments from a subtype-A/C dually infected woman with preferential genital replication of subtype C. Viral adaptation, spread and cell fusion ability were evaluated in vitro using peripheral blood mononuclear cells and HeLa-CD4-CCR5 cell lines, sequencing and cloning. Structural modeling was performed using a crystal structure of gp120-CD4-X5. Phylogenetic analysis was done using subtype-A, subtype-B and subtype-C sequences from blood and cervix of 37 infected women and database sequences.Results: We identified two envelope motifs, compact V1-V2 loops and V3-316T, which are found at high frequency throughout subtype-C evolution and affect gp120 interactions with CD4 and CCR5, respectively. When a V1-Delta 5 deletion or V3-A316T was incorporated into subtype A, each increased viral fusion and spread several fold in peripheral blood mononuclear cell and cell lines with low CCR5 expression. Structural modeling suggested the formation of an additional hydrogen bond between V3 and CCR5. Moreover, we found preferential selection of HIV with 316T and/or extremely short V1-V2 loops in cervices of three women infected with subtypes A/C, B or C.Conclusion: As CD(4+)-CCR(5+)-T cells are key targets for genital HIV infection and cervical selection can favor compact V1-V2 loops and 316T, which increase viral infectivity, we propose that these conserved subtype-C motifs may contribute to transmission and spread of this subtype. (C) 2009 Wolters Kluwer Health vertical bar Lippincotl Williams & Wilkins

Journal Keywords: Ccr5 ; Cervix ; Evolution ; Hiv-1 ; Phylogeny ; Subtype A ; Subtype C ; Transmission

Subject Areas: Biology and Bio-materials

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Added On: 23/06/2010 13:35

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