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Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests

BACKGROUND: The detection of HIV-1 p24 antigen in diagnostic tests relies on antibodies binding to conserved areas of the protein to cover the full range of HIV-1 subtypes. Using a panel of 43 different virus-like particles (VLPs) expressing Gag from clinical HIV-1 isolates, we previously found that...

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Autores principales: Vetter, Beatrice N., Orlowski, Vanessa, Niederhauser, Christoph, Walter, Louise, Schüpbach, Jörg
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625719/
https://www.ncbi.nlm.nih.gov/pubmed/26511217
http://dx.doi.org/10.1186/s12879-015-1174-7
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author Vetter, Beatrice N.
Orlowski, Vanessa
Niederhauser, Christoph
Walter, Louise
Schüpbach, Jörg
author_facet Vetter, Beatrice N.
Orlowski, Vanessa
Niederhauser, Christoph
Walter, Louise
Schüpbach, Jörg
author_sort Vetter, Beatrice N.
collection PubMed
description BACKGROUND: The detection of HIV-1 p24 antigen in diagnostic tests relies on antibodies binding to conserved areas of the protein to cover the full range of HIV-1 subtypes. Using a panel of 43 different virus-like particles (VLPs) expressing Gag from clinical HIV-1 isolates, we previously found that some highly sensitive tests completely failed to detect p24 of certain VLPs, seemingly unrelated to their subtype. Here we aimed to investigate the reason for this failure, hypothesising that it might be due to single amino acid variations in conserved epitopes. METHODS: Using amino acid alignment, we identified single amino acid variations at position 16 or 170 of p24, unique to those VLPs that failed to be detected in certain diagnostic tests. Through DNA-mutagenesis, these amino acids were changed to ones more commonly found at these positions. The impact of these changes on p24 detection was tested in commercial diagnostic tests as well as by Western Blot and ELISA, using epitope-specific antibodies. RESULTS AND CONCLUSIONS: Changing positions 16 or 170 to consensus amino acids restored the detection of p24 by the investigated diagnostic tests as well as by epitope-specific antibodies in Western Blot and ELISA. Hence, single amino acid changes in conserved epitopes can lead to the failure of p24 detection and thus to false-negative results. To optimise HIV diagnostic tests, they should also be evaluated using isolates which harbour less-frequent epitope variants.
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spelling pubmed-46257192015-10-30 Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests Vetter, Beatrice N. Orlowski, Vanessa Niederhauser, Christoph Walter, Louise Schüpbach, Jörg BMC Infect Dis Research Article BACKGROUND: The detection of HIV-1 p24 antigen in diagnostic tests relies on antibodies binding to conserved areas of the protein to cover the full range of HIV-1 subtypes. Using a panel of 43 different virus-like particles (VLPs) expressing Gag from clinical HIV-1 isolates, we previously found that some highly sensitive tests completely failed to detect p24 of certain VLPs, seemingly unrelated to their subtype. Here we aimed to investigate the reason for this failure, hypothesising that it might be due to single amino acid variations in conserved epitopes. METHODS: Using amino acid alignment, we identified single amino acid variations at position 16 or 170 of p24, unique to those VLPs that failed to be detected in certain diagnostic tests. Through DNA-mutagenesis, these amino acids were changed to ones more commonly found at these positions. The impact of these changes on p24 detection was tested in commercial diagnostic tests as well as by Western Blot and ELISA, using epitope-specific antibodies. RESULTS AND CONCLUSIONS: Changing positions 16 or 170 to consensus amino acids restored the detection of p24 by the investigated diagnostic tests as well as by epitope-specific antibodies in Western Blot and ELISA. Hence, single amino acid changes in conserved epitopes can lead to the failure of p24 detection and thus to false-negative results. To optimise HIV diagnostic tests, they should also be evaluated using isolates which harbour less-frequent epitope variants. BioMed Central 2015-10-29 /pmc/articles/PMC4625719/ /pubmed/26511217 http://dx.doi.org/10.1186/s12879-015-1174-7 Text en © Vetter et al. 2015 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Vetter, Beatrice N.
Orlowski, Vanessa
Niederhauser, Christoph
Walter, Louise
Schüpbach, Jörg
Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests
title Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests
title_full Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests
title_fullStr Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests
title_full_unstemmed Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests
title_short Impact of naturally occurring amino acid variations on the detection of HIV-1 p24 in diagnostic antigen tests
title_sort impact of naturally occurring amino acid variations on the detection of hiv-1 p24 in diagnostic antigen tests
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625719/
https://www.ncbi.nlm.nih.gov/pubmed/26511217
http://dx.doi.org/10.1186/s12879-015-1174-7
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