Performance evaluation of Meso Scale Discovery (MSD) quantitative serological assays for detection of binding (IgG, IgA, IgM) and ACE2 inhibitory antibody levels for SARS-CoV-2.

A performance evaluation of a quantitative research use only (RUO) immunological assay utilizing the Meso Scale Discovery (MSD) platform for assessing IgM, IgA, and IgG binding and SARS-CoV-2 pseudo-neutralization was performed. Comparative analyses of antibody quantification of IgA, IgG, and IgM isotypes against SARS-CoV-2 nucleocapsid, spike, Receptor Binding Domain (RBD) and N-Terminal Domain (NTD) antigens were performed using MSD multi-spot electro-chemiluminescent V-PLEX COVID-19 test kits, and two well characterized serological panels. Cross reactivity was assessed against COVID-19 negative/Influenza samples. Precision was assessed by comparing variation between duplicate values within run; accuracy was assessed by comparing values obtained across runs against expected values. The MSD IgG, IgA, and IgM binding, and ACE2 inhibitory antibody assays demonstrated acceptable precision and accuracy within the expected 20%/30% variability, respectively per manufacturer's protocol; no cross reactivity with influenza samples was observed. Different MSD plate configurations, multiple (two) MSD analysis instruments, and multiple operators did not impact antibody quantification; thus, confirming the robustness of both assays. Comparative analysis between MSD and commercial Euroimmun, Siemens ADVIA, and Beckman Coulter DXLTM ACCESS assays demonstrated better performance overall for the MSD assay.

IMPORTANCE

This work describes and validates the MSD platform, as a highly flexible, customizable, operator independent, and reliable platform for antibody assessment of COVID-19 response which is highly adaptable to immune assessment of emerging or re-emerging pathogens.