Use of V3 loop peptide-specific antibody evaluation for subtyping HIV-1: results of a vertical transmission study from São Paulo, Brazil.
Plasma samples obtained from 97 children enrolled in a longitudinal study of HIV-1 perinatal transmission in São Paulo, Brazil, were tested for the presence of specific V3-loop antibodies in order to determine the HIV-1 subtype circulating among them. A set of seven synthetic peptides representative of the predominant HIV-1 subtypes detected in Brazil was employed in an in-house enzyme immunoassay (EIA) using two different protocols, one of which permits identification of high avidity antibodies (HAAb). Using these approaches we were able to detect antibodies in 64 out of 97 children, independently of the HIV-1 infection status, indicating the presence of subtype B in all cases, except one, which could be considered to be of subtype F. Among subtype B cases, half of the samples reacted with the GWGR motif (type W is representative of Brazilian B strains). In the main, concordant results were obtained between peptide-EIA and HIV-1 status among infants, although in several cases of truly HIV-1 infected children, negative results could be observed. Thirteen mother-child pairs and four fathers were also evaluated, and the results confirmed subtype B to be the prevalent one among them, showing similar proportions of P and W types. Taken together, the results obtained identified subtype B (W and P) uniformly among adults and HIV-1 infected children from São Paulo, Brazil, and confirm vertical and sexual transmission of the predominant strains.
Caterino-de-Araujo
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Immunology Department, Instituto Adolfo Lutz, São Paulo, Brazil. caterino@usp.br
Casseb
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J
Hendry
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MR
D015492:AIDS Serodiagnosis; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D015658:HIV Infections / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008137:Longitudinal Studies; D012703:Serotyping
D000914:Antibodies, Viral