title: Emergence of X4 usage among HIV-1 subtype C: evidence for an evolving epidemic in South Africa.
abstract: This study investigated the genotype and phenotype of HIV-1 isolates of 20 South African AIDS patients. We found the highest percentage of CXCR4 usage among primary isolates, in which 30% efficiently utilized CXCR4 and exhibited the syncytium-inducing phenotype. Phylogenetic analysis of env confirmed that 19 of the 20 were subtype C, and syncytium-inducing viruses had genetic changes in the V3 loop, characteristic of CXCR4 usage. Results imply that the frequency of CXCR4-utilizing subtype C is increasing with time.
authors.affiliation: HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of Witwatersrand Medical School, Johannesburg, South Africa.
authors.forename: Bridgette J
authors.initials: BJ
authors.lastname: Connell
authors.forename: Katherine
authors.initials: K
authors.lastname: Michler
authors.forename: Alexio
authors.initials: A
authors.lastname: Capovilla
authors.forename: Willem D F
authors.initials: WD
authors.lastname: Venter
authors.forename: Wendy S
authors.initials: WS
authors.lastname: Stevens
authors.forename: Maria A
authors.initials: MA
authors.lastname: Papathanasopoulos
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000378:metabolism / Q000821:virology*; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D015331:Cohort Studies; D004279:DNA, Viral / Q000032:analysis; D004196:Disease Outbreaks; D005260:Female; D015752:Genes, env; D005838:Genotype; D015726:Giant Cells / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010641:Phenotype; D019713:Receptors, CCR5 / Q000378:metabolism*; D019718:Receptors, CXCR4 / Q000378:metabolism*; D013019:South Africa
chemical_list: D004279:DNA, Viral; D019713:Receptors, CCR5; D019718:Receptors, CXCR4