Browsing by Author "Grebe, Eduard"

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    Computational analysis of antibody dynamics identifies recent HIV-1 infection.
    (JCI insight, 2017-12-21) Seaton, Kelly E; Vandergrift, Nathan A; Deal, Aaron W; Rountree, Wes; Bainbridge, John; Grebe, Eduard; Anderson, David A; Sawant, Sheetal; Shen, Xiaoying; Yates, Nicole L; Denny, Thomas N; Liao, Hua-Xin; Haynes, Barton F; Robb, Merlin L; Parkin, Neil; Santos, Breno R; Garrett, Nigel; Price, Matthew A; Naniche, Denise; Duerr, Ann C; CEPHIA group; Keating, Sheila; Hampton, Dylan; Facente, Shelley; Marson, Kara; Welte, Alex; Pilcher, Christopher D; Cohen, Myron S; Tomaras, Georgia D
    Accurate HIV-1 incidence estimation is critical to the success of HIV-1 prevention strategies. Current assays are limited by high false recent rates (FRRs) in certain populations and a short mean duration of recent infection (MDRI). Dynamic early HIV-1 antibody response kinetics were harnessed to identify biomarkers for improved incidence assays. We conducted retrospective analyses on circulating antibodies from known recent and longstanding infections and evaluated binding and avidity measurements of Env and non-Env antigens and multiple antibody forms (i.e., IgG, IgA, IgG3, IgG4, dIgA, and IgM) in a diverse panel of 164 HIV-1-infected participants (clades A, B, C). Discriminant function analysis identified an optimal set of measurements that were subsequently evaluated in a 324-specimen blinded biomarker validation panel. These biomarkers included clade C gp140 IgG3, transmitted/founder clade C gp140 IgG4 avidity, clade B gp140 IgG4 avidity, and gp41 immunodominant region IgG avidity. MDRI was estimated at 215 day or alternatively, 267 days. FRRs in untreated and treated subjects were 5.0% and 3.6%, respectively. Thus, computational analysis of dynamic HIV-1 antibody isotype and antigen interactions during infection enabled design of a promising HIV-1 recency assay for improved cross-sectional incidence estimation.
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    Development of an international external quality assurance program for HIV-1 incidence using the Limiting Antigen Avidity assay.
    (PloS one, 2019-01) Keating, Sheila M; Rountree, Wes; Grebe, Eduard; Pappas, Andrea L; Stone, Mars; Hampton, Dylan; Todd, Christopher A; Poniewierski, Marek S; Sanchez, Ana; Porth, Cassandra G; Denny, Thomas N; Busch, Michael P; EQAPOL Limiting Antigen (LAg) Incidence Assay External Quality Assurance (EQA) Program
    Laboratory assays for identifying recent HIV-1 infections are widely used for estimating incidence in cross-sectional population-level surveys in global HIV-1surveillance. Adequate assay and laboratory performance are required to ensure accurate incidence estimates. The NIAID-supported External Quality Assurance Program Oversight Laboratory (EQAPOL) established a proficiency testing program for the most widely-used incidence assay, the HIV-1 Limiting Antigen Avidity EIA (LAg), with US Centers for Disease Control and Prevention (CDC)-approved kits manufactured by Sedia Biosciences Corporation and Maxim Biomedical. The objective of this program is to monitor the performance of participating laboratories. Four rounds of blinded external proficiency (EP) panels were distributed to up to twenty testing sites (7 North American, 5 African, 4 Asian, 2 South American and 2 European). These panels consisted of ten plasma samples: three blinded well-characterized HIV-1-seropositive samples that were included as replicates and an HIV-negative control. The seropositive samples spanned the dynamic range of the assay and are categorized as either recent or long-term infection. Participating sites performed the assay according to manufacturers' instructions and completed an online survey to gather information on kit manufacturer, lot of kit used, laboratory procedures and the experience of technicians. On average, fifteen sites participated in each round of testing, with an average of four sites testing with only the Maxim assay, seven testing with only the Sedia assay and five sites utilizing both assays. Overall, the Sedia and Maxim assays yielded similar infection status categorization across the laboratories; however, for most of the nine HIV+ samples tested, there were significant differences in the optical density readouts, ODn (N = 8) and OD (N = 7), between LAg kit manufacturers (p < 0.05 based on mixed effects models. The EQAPOL LAg program is important for monitoring laboratory performance as well as detecting variations between manufacturers of HIV-1incidence assays.
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    Evaluation of Commercially Available High-Throughput SARS-CoV-2 Serologic Assays for Serosurveillance and Related Applications.
    (Emerging infectious diseases, 2022-03) Stone, Mars; Grebe, Eduard; Sulaeman, Hasan; Di Germanio, Clara; Dave, Honey; Kelly, Kathleen; Biggerstaff, Brad J; Crews, Bridgit O; Tran, Nam; Jerome, Keith R; Denny, Thomas N; Hogema, Boris; Destree, Mark; Jones, Jefferson M; Thornburg, Natalie; Simmons, Graham; Krajden, Mel; Kleinman, Steve; Dumont, Larry J; Busch, Michael P
    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurveys can estimate cumulative incidence for monitoring epidemics, requiring assessment of serologic assays to inform testing algorithm development and interpretation of results. We conducted a multilaboratory evaluation of 21 commercial high-throughput SARS-CoV-2 serologic assays using blinded panels of 1,000 highly characterized specimens. Assays demonstrated a range of sensitivities (96%-63%), specificities (99%-96%), and precision (intraclass correlation coefficient 0.55-0.99). Durability of antibody detection was dependent on antigen and immunoglobulin targets; antispike and total Ig assays demonstrated more stable longitudinal reactivity than antinucleocapsid and IgG assays. Assays with high sensitivity, specificity, and durable antibody detection are ideal for serosurveillance, but assays demonstrating waning reactivity are appropriate for other applications, including correlation with neutralizing activity and detection of anamnestic boosting by reinfections. Assay performance must be evaluated in context of intended use, particularly in the context of widespread vaccination and circulation of SARS-CoV-2 variants.