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

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...

Full description

Saved in:
Bibliographic Details
Published in:BMC infectious diseases 2015-10, Vol.15 (1), p.468, Article 468
Main Authors: Vetter, Beatrice N, Orlowski, Vanessa, Niederhauser, Christoph, Walter, Louise, Schüpbach, Jörg
Format: Article
Language:English
Subjects:
AIDS Serodiagnosis - methods
Amino Acids - genetics
Antigens, Viral - immunology
Blotting, Western
Enzyme-Linked Immunosorbent Assay - methods
Epitopes - immunology
HIV Core Protein p24 - analysis
HIV Core Protein p24 - genetics
HIV Core Protein p24 - immunology
HIV-1 - immunology
HIV-1 - isolation & purification
Humans
Infectious diseases
Mutagenesis, Site-Directed
Reagent Kits, Diagnostic
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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. 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. 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.
ISSN:1471-2334
1471-2334
DOI:10.1186/s12879-015-1174-7