ABSTRACT
Abstract HIV diversity reflects multifactorial evolutionary forces, but monitoring subtype prevalence may provide clues to understanding the epidemic. In the Americas HIV-1 C is present at significant levels only in the southern states of Brazil. We describe in this study the presence of the HIV-1 C pol genome in 11.6% (95 CI 6-21%) of antiretroviral-naive individuals from São Paulo, the major city of South America, and 6.8% (95 CI 4-12%) from the second metropolitan area of the State of São Paulo, Brazil. Moreover, a significant growth trend of this subtype was documented among cases failing therapy in the area. Sequences were obtained by direct nested PCR from cDNA retrotranscribed from plasma RNA. Phylogenetic and amino acid signatures support an expansion from variants previously identified in southern Brazil. The evaluation of additional genomic regions (partial gag, envelope, and/or integrase) in samples with HIV-1 C at pol showed extensive recombination with clade B, observed in 47% of ARV-naive cases. The spread of HIV-1 C locally and to other areas of South America should be monitored as it may influence the dynamics of the epidemic.
Subject(s)
Drug Resistance, Viral/genetics , Genes, pol/genetics , HIV Infections/epidemiology , HIV-1/genetics , Adult , Base Sequence , Brazil/epidemiology , Genetic Variation , HIV Infections/genetics , Humans , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , RNA, Viral/analysis , RNA, Viral/genetics , Sequence Alignment , Sequence Analysis, DNA , Treatment OutcomeSubject(s)
Anti-Retroviral Agents/therapeutic use , HIV Infections/drug therapy , HIV-1/genetics , Adult , Brazil , DNA, Viral/genetics , Drug Resistance, Viral/genetics , Female , Genotype , HIV Infections/virology , Humans , Male , Molecular Sequence Data , Mutation/genetics , Proviruses/genetics , RNA, Viral/geneticsABSTRACT
The main objective of the present study was to assess the specificity and sensitivity of a modified assay using short synthetic peptides of the V3 region of HIV-1 gp120, which is the main target for neutralizing antibodies. Results from an enzyme immunoassay (EIA) employing a panel of synthetic peptides of HIV-1 subtypes and using urea washes to detect high avidity antibodies (AAV3) were compared with those obtained by the heteroduplex mobility assay and DNA sequencing. The EIA correctly typed 100% of subtype B (sensitivity = 1.0; specificity = 0.95), 100% of HIV-1 E samples (sensitivity = 1.0; specificity = 1.0), and 95% of subtype C specimens (sensitivity = 0.95; specificity = 0.94). In contrast, only 50% of subtype A (sensitivity = 0.5; specificity = 0.95), 60% of subtype D (sensitivity = 0.6; specificity = 1.0), and 28% of subtype F samples (sensitivity = 0.28; specificity = 0.95) were correctly identified. This approach was also able to discriminate in a few samples antibodies from patients infected with B variants circulating in Brazil and Thailand that reacted specifically. The assays described in this study are relatively rapid and simple to perform compared to molecular approaches and can be used to screen large numbers of serum or plasma samples. Moreover, the classification in subtypes (genotypes) may overestimate HIV-1 diversity and a classification into serotypes, based on antigenic V3 diversity or another principal neutralization domain, may be more helpful for vaccine development and identification of variants.
Subject(s)
Antibody Affinity , HIV Antibodies/immunology , HIV Envelope Protein gp120/immunology , HIV Infections/immunology , HIV-1/classification , Immunoenzyme Techniques/methods , Peptide Fragments/immunology , Amino Acid Sequence , Base Sequence , HIV Antibodies/blood , HIV Infections/virology , HIV-1/immunology , Humans , Molecular Sequence Data , Sensitivity and Specificity , Sequence Homology , SerotypingABSTRACT
The main objective of the present study was to assess the specificity and sensitivity of a modified assay using short synthetic peptides of the V3 region of HIV-1 gp120, which is the main target for neutralizing antibodies. Results from an enzyme immunoassay (EIA) employing a panel of synthetic peptides of HIV-1 subtypes and using urea washes to detect high avidity antibodies (AAV3) were compared with those obtained by the heteroduplex mobility assay and DNA sequencing. The EIA correctly typed 100 percent of subtype B (sensitivity = 1.0; specificity = 0.95), 100 percent of HIV-1 E samples (sensitivity = 1.0; specificity = 1.0), and 95 percent of subtype C specimens (sensitivity = 0.95; specificity = 0.94). In contrast, only 50 percent of subtype A (sensitivity = 0.5; specificity = 0.95), 60 percent of subtype D (sensitivity = 0.6; specificity = 1.0), and 28 percent of subtype F samples (sensitivity = 0.28; specificity = 0.95) were correctly identified. This approach was also able to discriminate in a few samples antibodies from patients infected with B variants circulating in Brazil and Thailand that reacted specifically. The assays described in this study are relatively rapid and simple to perform compared to molecular approaches and can be used to screen large numbers of serum or plasma samples. Moreover, the classification in subtypes (genotypes) may overestimate HIV-1 diversity and a classification into serotypes, based on antigenic V3 diversity or another principal neutralization domain, may be more helpful for vaccine development and identification of variants
