Highly sensitive and specific multiplex antibody assays to quantify immunoglobulins M, A and G against SARS-CoV-2 antigens
clinical diagnostics
Authors:Dobaño et al.
Link to paper: https://doi.org/10.1101/2020.06.11.147363
Journal/ Pre-Print:BioRxiv
Tags: Clinical/ Diagnostics
Research Highlights
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Developed a sensitive multiplex assay using quantitative suspension array technology (qSAT)s which included RBD, S1, S2, S, M and N SARS-CoV-2 antigens
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Observed some cross-reactivity of negative control (pre-pandemic) sera for M, S2 and N SARS-CoV-2 antigens
Summary
The authors developed a time-optimised qSAT assay based on a Luminex platform which measured antibodies IgG, IgM, and IgA against SARS-CoV-2 antigens RBD, S1, S2, S (spikeprotein and its components), M (membrane) and N (nucleoprotein). The authors use of multiplexing with different combinations of antibody isotype and antigen increased specificity and sensitivity. High specificity and sensitivity was observed against 128 pre-pandemic plasma negative controls and 115 positive control plasmas. Cross-reactivity to M, S2 and N antigens was observed for some negative controls. The authors note there is further work to validate this potentially useful tool, which could then be applied to vaccine development and/or antibody studies.
Impact for SARS-CoV2/COVID19 research efforts
Develop diagnostic tools for SARS-CoV2/COVID19
Others: Develop a multiplexed antibody detection tool for application of post-vaccine efficacy and post-infection antibody studies
Study Type
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In vitro study
Strengths and limitations of the paper
Novelty: Developed a new multiplexing tool to study antibody responses to multiple antigens of SARS-CoV-2
Standing in the field: Builds on other serological assays, but lacks supporting informationfrom conventional ELISAs
Appropriate statistics:Good statistics with specificities and sensitivities. However, averages with error bars would have made comparative data clearer
Viral model used:SARS-CoV-2 antigens
Translatability:Possible research tool for vaccine development and/or antibody studies
Main limitations:
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Volume of sample used per test compared to volume used in an ELISA is not clear
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No comparison of multiplex test with ELISA to show comparability
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Would have been nice to have had a comparison of antibody-antigen detection over the four different time points from onset of symptoms
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M protein purity described as being “not high”, would have been better for robustness of assay to have been purer
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Short times described as a benefit of the assay. However, no mention of time required to carry out assay
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No conclusion reached on which antibody-antigen combinations had the most potential