ArticleJournal of immunological methods2023
A FluoroSpot B assay for the detection of IgA and IgG SARS-CoV-2 spike-specific memory B cells: Optimization and qualification for use in COVID-19 vaccine trials.
Article in Journal of immunological methods, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
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Who cites it
4 citing papers in PubMed, 12 citations in OpenAlex.
- Monitoring Memory B Cells by Next-Generation ImmunoSpotMethods in molecular biology (Clifton, N.J.) · 2024Article
- Four-Color ImmunoSpotMethods in molecular biology (Clifton, N.J.) · 2024Article
- High-Plex ELISPOT: FOLISPOT Based on Fluorescence Detection and DNA Complementary Pairing.Methods in molecular biology (Clifton, N.J.) · 2024Article
- Non-cross-reactive epitopes dominate the humoral immune response to COVID-19 vaccination - kinetics of plasma antibodies, plasmablasts and memory B cells.Frontiers in immunology · 2024Article
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4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThe generation of antigen-specific memory B cells is crucial to the long-term effectiveness of vaccines. When the protective antibodies circulating in the blood wane, memory B cells (MBC) can be rapidly reactivated and differentiated into antibody-secreting cells during a new infection. Such MBC responses are considered to be key in providing long-term protection after infection or vaccination. Here, we describe the optimization and qualification of a FluoroSpot assay to measure MBCs directed against the SARS-CoV-2 spike protein in the peripheral blood, for use in COVID-19 vaccine trials.
methodsWe developed a FluoroSpot assay enabling simultaneous enumeration of B cells secreting IgA or IgG spike-specific antibodies after polyclonal stimulation of peripheral blood mononuclear cells (PBMCs) with interleukin-2 and the toll-like receptor agonist R848 for 5 days. The antigen coating was optimized using a capture antibody directed against the spike subunit-2 glycoprotein of SARS-CoV-2 to immobilize recombinant trimeric spike protein onto the membrane.
resultsCompared to a direct spike protein coating, the addition of a capture antibody increased the number and the quality of detected spots for both spike-specific IgA and IgG secreting cells in PBMCs from COVID-19 convalescents. The qualification showed good sensitivity of the dual-color IgA-IgG FluoroSpot assay, with lower limits of quantitation of 18 background-subtracted (BS) antibody-secreting cells (ASCs)/well for spike-specific IgA and IgG responses. Linearity was demonstrated at values ranging from 18 to 73 and from 18 to 607 BS ASCs/well for spike-specific IgA and IgG, respectively, as was precision, with intermediate precision (percentage geometric coefficients of variation) of 12% and 26% for the proportion of spike-specific IgA and IgG MBCs (ratio specific/total IgA or Ig). The assay was specific, since no spike-specific MBCs were detected in PBMCs from pre-pandemic samples; the results were below the limit of detection of 17 BS ASCs/well.
conclusionsThese results show that the dual-color IgA-IgG FluoroSpot provides a sensitive, specific, linear, and precise tool to detect spike-specific MBC responses. This MBC FluoroSpot assay is a method of choice for monitoring spike-specific IgA and IgG MBC responses induced by COVID-19 candidate vaccines in clinical trials.
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