RESUMO
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.
Assuntos
Afinidade de Anticorpos , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/classificação , Técnicas Imunoenzimáticas/métodos , Fragmentos de Peptídeos/imunologia , Sequência de Aminoácidos , Sequência de Bases , Anticorpos Anti-HIV/sangue , Infecções por HIV/virologia , HIV-1/imunologia , Humanos , Dados de Sequência Molecular , Sensibilidade e Especificidade , Homologia de Sequência , SorotipagemRESUMO
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
Assuntos
Humanos , Afinidade de Anticorpos , Anticorpos Anti-HIV , Proteína gp120 do Envelope de HIV , Infecções por HIV , HIV-1 , Técnicas Imunoenzimáticas , Sequência de Aminoácidos , Sequência de Bases , Anticorpos Anti-HIV , Infecções por HIV , HIV-1 , Dados de Sequência Molecular , Sensibilidade e Especificidade , Homologia de Sequência , Sorologia , SorotipagemRESUMO
Human immunodeficiency virus (HIV-1)-infected subjects with acquired immunodeficiency syndrome (AIDS) are often infected with multiple pathogens. In particular, HTLV-I and HTLV-II infections have been found more frequently in AIDS patients than in asymptomatic individuals in Europe and Japan. We carried out a serosurvey among asymptomatic HIV-1-infected subjects in São Paulo, Brazil and compared our results with those of other investigators. In this study, we found HTLV infection in 1.5% of 266 asymptomatic and 14% of 28 AIDS patients. Epidemiological data obtained from patients pointed out the use of intravenous drugs as the principal risk factor for acquiring retroviruses. In conclusion, our results are in accordance with other studies done in Brazil and elsewhere where the principal risk group for HIV/HTLV-I/II coinfection was IDU.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , HIV-1 , Infecções por HTLV-I/epidemiologia , Infecções por HTLV-II/epidemiologia , Adolescente , Adulto , Idoso , Brasil , Feminino , Infecções por HTLV-I/complicações , Infecções por HTLV-II/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de RiscoAssuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções por HTLV-I/diagnóstico , Infecções por HTLV-II/diagnóstico , Abuso de Substâncias por Via Intravenosa , Infecções Oportunistas Relacionadas com a AIDS/sangue , Infecções Oportunistas Relacionadas com a AIDS/imunologia , Western Blotting , Brasil , Ensaio de Imunoadsorção Enzimática , Técnica Indireta de Fluorescência para Anticorpo , Infecções por HTLV-I/complicações , Infecções por HTLV-I/imunologia , Infecções por HTLV-II/complicações , Infecções por HTLV-II/imunologia , Humanos , Abuso de Substâncias por Via Intravenosa/complicaçõesRESUMO
Viral DNA sequences were determined over the V3 region of env from 28 infected individuals living in the high HIV-1 prevalence Brazilian cities of Rio de Janeiro and São Paulo. Twenty-six belonged to envelope sequence subtype B, prevalent in North America and Europe, and one was classified as subtype F, found recently in Brazil and in Romania (one appeared to be a B/F recombinant). Octameric sequences at the tip of the subtype B V3 loops were variable and distinct from those prevalent in North America and Europe. The GPGR motif, prevalent in North American/European strains, was found in only 8 (28.5%) sequences, whereas GWGR was found in 12 (43%) and novel sequences in 8 (28.5%). Brazilian subtype B sequences also diverged from the consensus North American/European strains over the remainder of the V3 loop. These results suggest that Brazilian HIV-1 B strains may have important antigenic differences from prototype subtype B strains currently being evaluated for use in HIV vaccines. These results should be taken into account for future vaccine programs in Brazil.
Assuntos
Proteína gp120 do Envelope de HIV/genética , Infecções por HIV/microbiologia , HIV-1/genética , HIV-1/isolamento & purificação , Fragmentos de Peptídeos/genética , Polimorfismo Genético , Vacinas contra a AIDS/isolamento & purificação , Sequência de Aminoácidos , Sequência de Bases , Brasil , Primers do DNA/genética , DNA Viral/genética , Feminino , Genes env , HIV-1/classificação , Humanos , Masculino , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , RNA/genética , Homologia de Sequência de AminoácidosRESUMO
PIP: A study was conducted of the reactivity of 85 plasma samples from HIV-1 seropositive persons living in Brazil. Five HIV-1 plasma samples had synthetic peptides from the V3 region isolates (IIIB, MN, SC, WMJ-2, and RF). There was a low reactivity (59%) with HIV-1 isolate MN derived PND peptides, while most studies report a 90% or higher reactivity. Brazilian HIV-1 seropositive sera had lower reactivity with MN isolate PND peptides than sera from other countries. Researchers used 5 HIV-1 MN isolate PND peptides from other sources to analyze the same plasma to confirm the study's results. The HIV-1 MN isolate PND peptides had different amino acid sequences, but all had the GPGR top of the V3 loop. 52% of the Brazilian plasma recognized V3 peptides, 55% for 48 peptides, 56% for C52 peptides, and 49% for C53 pep tides. Only 27% of the Brazilian plasma recognized the C54 peptide. There was considerable overlapping reactivity, however. For example, 65% of the V3 MN reactive plasma also recognized the C52 MN peptide and the C53 MN peptide. The overlap between C52 MN and C53 MN was 69%. These findings suggest that, in the Brazilian study population, at least 2 different anti-MN-PND antibody specificities directed against amino acid sequences including the GPGR top of the V3 loop exist (an epitope including PNY[NKRKRIHIGPGR] and the epitope including [KRKRIHIGPGR]AFY). 86% of the plasma reacted with at least 20% of the MN PND peptides, which equals reactivities in other studies. 96% of the Brazilian plasma were positive for neutralizing antibodies based on overlap of peptide recognition and HIV-1 MN isolate neutralization (titers = 1:100-1:52,600). Recognition of the V3 loop of the HIV-1 MN isolate in sera from HIV-1 positive persons in Brazil has two different antibody specificities. Most of the Brazilian plasma recognize the N terminal arm, which consists of the GPGR top of the V3 loop.^ieng
Assuntos
Anticorpos Anti-HIV/análise , Proteína gp120 do Envelope de HIV/imunologia , Soropositividade para HIV/imunologia , Fragmentos de Peptídeos/imunologia , Sequência de Aminoácidos , Brasil , Humanos , Dados de Sequência MolecularRESUMO
Recent reports have indicated the possibility that HIV-2 has been introduced into groups at risk for AIDS in Brazil. We studied sera collected in 1987 and 1988 from 1,821 at-risk individuals from diverse regions in Brazil. Of the 1,821 sera, 367 (20%) were confirmed as being positive for HIV-1 antibodies by enzyme-linked immunosorbent assay (ELISA), immunofluorescence (IF), and Western blot. An additional 33 (2%) sera displayed some reactivity to HIV-2-infected cells by IF. All 33 sera were subsequently tested in HIV-1 and HIV-2 Western blots as well as an ELISA using HIV-1- or HIV-2-specific peptides. All sera were confirmed as positive for HIV-1 and negative for HIV-2 antibodies in both assays. We conclude that caution should be used in the interpretation of serologic cross-reactivity between HIV-1 and HIV-2 and that there is no evidence that HIV-2 has entered groups at risk for HIV infection in Brazil.