title: Genetic and biologic characterization of HIV type 1 subtype C isolates from south Brazil.
abstract: The molecular and biological properties of HIV-1 subtype C strains from South Brazil were investigated. We sequenced gag and env fragments of viruses from 22 HIV-1-infected individuals from Porto Alegre City, which has the highest frequency of subtype C in the country. The sequences were then compared with other subtype B, C, and F strains isolated in Brazil and other countries using phylogenetic methods. Amino acid signatures were identified and correlated with phenotypic characteristics. We identified six strains with subtype C (27.3%), eight subtype B (36.4%), one subtype F (4.5%), six C/B recombinants (27.3%), and one B/F recombinant (4.5%). The Brazilian subtype C sequences formed a unique phylogenetic group and presented 6 and 18 specific amino acid signatures in gag and env, respectively. Three distinct patterns of C/B recombinants presented characteristic Brazilian amino acid substitutions. Subtype C viruses were predominantly R5 and non-syncytium-inducing, while C/B recombinants were R5/X4 and syncytium-inducing viruses. These findings suggest that subtype C viruses circulating in Brazil are the result of a unique introduction into the country. Recombination events between subtypes B and C have been occurring frequently for more than 10 years in South Brazil. Biological characterization confirms the hypothesis that subtype C is distinct from the others in the evolution of coreceptor utilization.
authors.affiliation: Laboratório Avançado de Saúde Pública, Centro de Pesquisa Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Joana P
authors.initials: JP
authors.lastname: Monteiro
authors.forename: Geraldo A
authors.initials: GA
authors.lastname: Ferraro
authors.forename: Túlio
authors.initials: T
authors.lastname: Oliveira
authors.forename: Luciano Z
authors.initials: LZ
authors.lastname: Goldani
authors.forename: Simone
authors.initials: S
authors.lastname: Kashima
authors.forename: Luiz C J
authors.initials: LC
authors.lastname: Alcantara
authors.forename: Mariza G
authors.initials: MG
authors.lastname: Morgado
authors.forename: Dumith Chequer
authors.initials: DC
authors.lastname: Bou-Habib
authors.forename: Bernardo
authors.initials: B
authors.lastname: Galvão-Castro
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D001938:Brazil; D016384:Consensus Sequence; D004279:DNA, Viral / Q000032:analysis; D015686:Gene Products, env / Q000235:genetics; D015683:Gene Products, gag / Q000235:genetics; D015752:Genes, env; D015750:Genes, gag; D015658:HIV Infections / Q000382:microbiology*; D015497:HIV-1 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D004279:DNA, Viral; D015686:Gene Products, env; D015683:Gene Products, gag