Generation of a Recombinant Gag Virus-Like-Particle Panel for the Evaluation of p24 Antigen Detection by Diagnostic HIV Tests

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Abstract

Background

Detection of HIV-1 p24 antigen permits early identification of primary HIV infection and timely intervention to limit further spread of the infection. Principally, HIV screening should equally detect all viral variants, but reagents for a standardised test evaluation are limited. Therefore, we aimed to create an inexhaustible panel of diverse HIV-1 p24 antigens.

Methods

We generated a panel of 43 recombinantly expressed virus-like particles (VLPs), containing the structural Gag proteins of HIV-1 subtypes A-H and circulating recombinant forms (CRF) CRF01_AE, CRF02_AG, CRF12_BF, CRF20_BG and group O. Eleven 4 ^th generation antigen/antibody tests and five antigen-only tests were evaluated for their ability to detect VLPs diluted in human plasma to p24 concentrations equivalent to 50, 10 and 2 IU/ml of the WHO p24 standard. Three tests were also evaluated for their ability to detect p24 after heat-denaturation for immune-complex disruption, a pre-requisite for ultrasensitive p24 detection.

Results

Our VLP panel exhibited an average intra-clade p24 diversity of 6.7%. Among the 4 ^th generation tests, the Abbott Architect and Siemens Enzygnost Integral 4 had the highest sensitivity of 97.7% and 93%, respectively. Alere Determine Combo and BioRad Access were least sensitive with 10.1% and 40.3%, respectively. Antigen-only tests were slightly more sensitive than combination tests. Almost all tests detected the WHO HIV-1 p24 standard at a concentration of 2 IU/ml, but their ability to detect this input for different subtypes varied greatly. Heat-treatment lowered overall detectability of HIV-1 p24 in two of the three tests, but only few VLPs had a more than 3-fold loss in p24 detection.

Conclusions

The HIV-1 Gag subtype panel has a broad diversity and proved useful for a standardised evaluation of the detection limit and breadth of subtype detection of p24 antigen-detecting tests. Several tests exhibited problems, particularly with non-B subtypes.

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Most cited references 31

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Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection.

Lorraine Peddada, Steven Kleinman, Lal B. Rawal … (2003)

The characterization of primary HIV infection by the analysis of serial plasma samples from newly infected persons using multiple standard viral assays. A retrospective study involving two sets of archived samples from HIV-infected plasma donors. (A) 435 samples from 51 donors detected by anti-HIV enzyme immunoassays donated during 1984-1994; (B) 145 specimens from 44 donors detected by p24 antigen screening donated during 1996-1998. Two US plasma products companies. The timepoints of appearance of HIV-1 markers and viral load concentrations during primary HIV infection. The pattern of sequential emergence of viral markers in the 'A' panels was highly consistent, allowing the definition and estimation of the duration of six sequential stages. From the 'B' panels, the viral load at p24 antigen seroconversion was estimated by regression analysis at 10 000 copies/ml (95% CI 2000-93 000) and the HIV replication rate at 0.35 log copies/ml/day, corresponding to a doubling time in the preseroconversion phase of 20.5 h (95% CI 18.2-23.4 h). Consequently, an RNA test with 50 copies/ml sensitivity would detect HIV infection approximately 7 days before a p24 antigen test, and 12 days before a sensitive anti-HIV test. The sequential emergence of assay reactivity allows the classification of primary HIV-1 infection into distinct laboratory stages, which may facilitate the diagnosis of recent infection and stratification of patients enrolled in clinical trials. Quantitative analysis of preseroconversion replication rates of HIV is useful for projecting the yield and predictive value of assays targeting primary HIV infection.

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A multicenter observational study of the potential benefits of initiating combination antiretroviral therapy during acute HIV infection.

Brian Conway, Lei Wang, J Michael Kilby … (2006)

Uncontrolled studies have suggested a benefit, after treatment discontinuation, of initiating highly active antiretroviral therapy (HAART) during primary human immunodeficiency virus (HIV) infection. We assessed whether initiation of HAART within 2 weeks of (acute treatment) or between 2 weeks and 6 months after (early treatment) HIV seroconversion was associated with improvements in the viral load and the CD4+ T cell count after discontinuation of treatment in an observational cohort. Subjects from the multicenter Acute Infection and Early Disease Research Program cohort were enrolled in the present study within 6 months of HIV seroconversion and self-selected whether to initiate HAART. Subjects who received acute (n=13) or early (n=45) treatment received HAART for at least 12 weeks and then subsequently stopped treatment, whereas untreated subjects (n=337) declined treatment. HIV RNA levels and CD4+ T cell counts at 24, 48, and 72 weeks after treatment cessation in the 2 treatment groups were compared with those noted in the untreated group during the same periods of observation after enrollment. The acute treatment group had lower mean HIV RNA levels at 24 weeks without therapy (-0.48 log(10) copies/mL [95% confidence interval {CI}, -0.82 to -0.13 log(10) copies/mL]) and higher mean CD4+ T cell counts (112 cells/ mu L [95% CI, 20-205 cells/ microL]), compared with the untreated group at 24 weeks. The differences in the laboratory values for the acute treatment group versus the untreated group at 72 weeks without therapy were as follows: for the HIV RNA level, -0.35 log(10) copies/mL (95% CI, -0.91 to 0.21 log(10) copies/mL) and, for the CD4 T+ cell count, 112 cells/ microL (95% CI, -15 to 213 cells/ microL). The early treatment group had lower HIV RNA levels at 24 weeks than did the untreated group, but differences were no longer apparent by week 48; CD4+ T cell counts were higher in the early treatment group at week 24 (116 cells/ microL [95% CI, 75-157 cells/ microL]) and week 72 (70 cells/ microL [95% CI, 2-138 cells/ microL]). Initiation of HAART within 2 weeks of antibody seroconversion was associated with viral load and CD4+ T cell count benefits for 24 weeks after termination of HAART, with there being trends toward a longer-term benefit. Later initiation of HAART was associated with a persistent but decreasing CD4+ T cell count benefit and a loss of the viral load benefit by week 72 after discontinuation of treatment.

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Detection of acute HIV infection: a field evaluation of the determine® HIV-1/2 Ag/Ab combo test.

Sarah E. Rutstein, Deborah Kamwendo, Gift Kamanga … (2012)

Most human immunodeficiency virus (HIV) point-of-care tests detect antibodies (Ab) but not p24 antigen (Ag) or RNA. In the absence of antibodies, p24 antigen and RNA typically indicate acute HIV infection. We conducted a field evaluation of the Determine® HIV-1/2 Ag/Ab Combo rapid test (Combo RT). The antigen portion of the Combo RT (for acute HIV infection) was compared with a Roche Monitor HIV RNA polymerase chain reaction assay. The antibody portion of Combo RT (for established HIV infection) was compared with rapid test algorithms. Participants were enrolled at a sexually transmitted infection clinic and HIV testing and counseling center in Lilongwe, Malawi. Rapid testing was conducted with parallel testing in the clinic and serial testing in the center. The Combo RT was performed in clinic participants with negative or discordant antibody results and in all center participants. Of the participants 838 were HIV negative, 163 had established HIV infection, and 8 had acute HIV infection. For detecting acute HIV infection, the antigen portion had a sensitivity of 0.000 and a specificity of 0.983. For detecting established HIV infection, the antibody portion had a sensitivity of 0.994 and a specificity of 0.992. Combo RT displayed excellent performance for detecting established HIV infection and poor performance for detecting acute HIV infection. In this setting, Combo RT is no more useful than current algorithms.

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Author and article information

Contributors

Jean-Luc E. P. H. Darlix: Role: Editor

Journal

Journal ID (nlm-ta): PLoS One

Journal ID (iso-abbrev): PLoS ONE

Journal ID (publisher-id): plos

Journal ID (pmc): plosone

Title: PLoS ONE

Publisher: Public Library of Science (San Francisco, USA )

ISSN (Electronic): 1932-6203

Publication date Collection: 2014

Publication date (Electronic): 24 October 2014

Volume: 9

Issue: 10

Electronic Location Identifier: e111552

Affiliations

[1 ]Swiss National Center for Retroviruses (SNCR), Institute of Medical Virology, University of Zürich, Zürich, Switzerland

[2 ]Institute of Tropical Medicine (ITG), Clinical Science, Antwerp, Belgium

[3 ]Blood Transfusion Service, Swiss Red Cross Berne (BSDSRK), Berne, Switzerland

[4 ]University Hospital, Service of Immunology and Allergy, CHUV, Lausanne, Switzerland

[5 ]Labor Synlab Luzern, Lucerne, Switzerland

[6 ]Viollier AG, Allschwil, Switzerland

[7 ]Center for Laboratory Medicine (ZLMSG), St. Gallen, Switzerland

[8 ]Department Biomedicine, Haus Petersplatz, University of Basel, Basel, Switzerland

[9 ]University Hospital, Clinic for Immunology, Zurich, Switzerland

[10 ]Department of Infectious Diseases, Cantonal Hospital St. Gallen (KSSG), St. Gallen, Switzerland

[11 ]German Red Cross Blood Transfusion Service West (DRK), Hagen, Germany

[12 ]University of Berne, Institute of Infectious Diseases, Berne, Switzerland

[13 ]University Hospitals (HUG), Laboratory of Virology, Genève, Switzerland

Institut National de la Santé et de la Recherche Médicale, France

Author notes

* E-mail: vetter.beatrice@ 123456virology.uzh.ch

Competing Interests: The authors have read the journal's policy and one author of this manuscript has the following competing interests: SY has received educational grants from Merck Sharp & Dohme and Gilead. The following authors were associated with private companies when this work was done: MB with Labor Synlab Luzern and DC with Viollier AG. Both companies are commercial diagnostic laboratories. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. All other authors have declared that no competing interests exist.

Conceived and designed the experiments: BNV JS. Performed the experiments: BNV VO KF CN VA MB DC GD TK SR PS VS FSR SY. Analyzed the data: BNV JS JB. Contributed reagents/materials/analysis tools: CS. Wrote the paper: BNV JS.

Article

Publisher ID: PONE-D-14-30482

DOI: 10.1371/journal.pone.0111552

PMC ID: 4208835

PubMed ID: 25343245

SO-VID: ba60ecfd-1867-454c-aaef-2a5b1b05da23

License:

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

History

Date received : 8 July 2014

Date accepted : 28 September 2014

Page count

Pages: 9

Funding

The authors have no support or funding to report.

Custom metadata

Data Availability The authors confirm that all data underlying the findings are fully available without restriction. VLP Gag-PR sequences are available at the NIH genetic sequence database GenBank, accesson numbers KJ689249-KJ689290.

Generation of a Recombinant Gag Virus-Like-Particle Panel for the Evaluation of p24 Antigen Detection by Diagnostic HIV Tests

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Abstract

Background

Methods

Results

Conclusions

Related collections

PLOS Climate

Most cited references 31

Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection.

A multicenter observational study of the potential benefits of initiating combination antiretroviral therapy during acute HIV infection.

Detection of acute HIV infection: a field evaluation of the determine® HIV-1/2 Ag/Ab combo test.

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