The EDI ELISA produced a clear distinction between positive and negative samples at a neutralizing antibody titer of 1/43. specificity for detection of SARS-CoV-2 IgG, obvious from lack of reactivity to SARS-CoV-2 antigens despite significant reactivity to endemic coronavirus antigens in pre-pandemic samples. SARS-CoV-2 IgG positive samples reacted weakly to SARS-CoV spike but not to MERS-CoV. While the VaxArray platform had overall comparable results to the spike and nucleocapsid IgG ELISAs, results were more similar to the spike antigen ELISA and the platform displayed a higher sensitivity and specificity than both ELISAs. Samples with FRNT titers below 1/23 reported unfavorable on VaxArray, while positive samples on VaxArray experienced significantly higher neutralizing antibody titers. These results suggest that the VaxArray Coronavirus SeroAssay performs with high sensitivity and specificity for the detection of SARS-CoV-2 IgG, and positive results on the platform indicate SARS-CoV-2 neutralizing activity. Keywords:COVID-19, SARS-CoV-2, Antigen array, Spike antigen, SARS-CoV-2 IgG Abbreviations:COVID-19, Coronavirus Disease 2019; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus-2; CoV, Coronavirus; S, Spike protein; RBD, Receptor Binding Domain name; ELISA, Enzyme Linked Immunosorbent Assay; FDA, Food and Drug Administration; EUA, Emergency Use Authorization; CCP, COVID-19 Convalescent Plasma; RPP, Respiratory Pathogen Panel; EDI, Epitope Diagnostic Inc; HRP, Horseradish peroxidase; TMB, Tetramethyl Benzidine; FRNT, Focus Reduction Neutralizing Antibody Test; OD, Optical Density == 1. Introduction == A plethora of antibody assays Heptasaccharide Glc4Xyl3 have been developed in response to the novel Coronavirus Disease-19 (COVID-19) pandemic that continues to spread across the globe. Analysis of SARS-CoV-2 antibodies has power for understanding the prevalence of contamination within communities (Angulo et al., Heptasaccharide Glc4Xyl3 2021;Bajema et al., 2020;Koopmans and Haagmans, 2020;Tanne, 2020), providing evidence of past infection or recent contamination when viral detection by PCR is usually unfavorable (Anderson et al., 2020;Jia et al., 2021), and Heptasaccharide Glc4Xyl3 for the analysis of convalescent plasma that has been used therapeutically to treat COVID-19 (DomBourian et al., 2020;Shen et al., 2020). Additionally, with the implementation of COVID-19 vaccination, analysis of the Heptasaccharide Glc4Xyl3 antibody response to these vaccines is necessary in order to understand both the short-term immune response and the longevity of the immune response. Initially, the development of antibody assays was fraught with issues of cross-reactivity to pre-existing antibodies to the non-SARS-CoV-2 human coronaviruses (hCoVs) hCoV-HKU1, hCoV-OC43, hCoV-229E and hCoV-NL63 and therefore, lower specificity of antibody detection. Over the course of Rabbit polyclonal to Zyxin the past several months, antibody assays with high specificity and sensitivity (depending on the timing of sample collection post contamination) have been developed and implemented in clinical laboratories (Abbasi, 2020;National S-C-SAEG, 2020). However, few have incorporated antigens from related hCoVs to address the question of antibody specificity. The VaxArray Coronavirus SeroAssay incorporates the S1 domain name from your spike (S) protein of SARS-CoV, MERS-COV, and either the S1 domain name or the full-length S protein of four human endemic CoVs, hCoV-HKU1, hCoV-OC43, hCoV-229E and hCoV-NL63 along with the full-length S protein, the receptor binding domain name (RBD), and the proximal extracellular fusion domain name (S2) of the SARS-CoV-2 S antigen in a single assay (Dawson et al., 2021). Each of these antigens is spotted, in nine replicates, onto a functionalized glass slide in a 9 9 grid. When incubated with human serum followed by anti-human IgG conjugated to a fluorescent molecule, reactivity to each antigen appear as unique fluorescent spots that can be quantified as relative fluorescent units. Inclusion of the S antigen from related CoVs enables evaluation of the specificity of the antibody response to SARS-CoV-2. Here we compare the performance of the VaxArray Coronavirus SeroAssay with a CE-marked and clinically validated ELISA and an FDA Emergency Use Authorization (EUA) approved assay for analysis of SARS-CoV-2 IgG antibodies. Additionally, we compare the VaxArray Coronavirus SeroAssay with a functional assay for SARS-CoV-2 neutralizing antibodies. == 2. Materials and methods == == 2.1. Donors == Children’s Hospital Colorado became eligible Heptasaccharide Glc4Xyl3 to collect COVID-19 Convalescent Plasma (CCP) after registering with the FDA on March 31, 2020. According to the FDA’s requirements, individuals were eligible to participate in the CCP donor program if they experienced.