DOI: 10.7910/dvn/6wo6tg
title: Replication Data for: Diagnostic Accuracy of an Immunoassay Using Avidity-Enhanced Polymeric Peptides for SARS-CoV-2 Antibody Detection

description: &lt;h2&gt;Diagnostic Accuracy of an Immunoassay Using Avidity-Enhanced Polymeric Peptides for SARS-CoV-2 Antibody Detection&lt;/h2&gt;

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; There is a need for &lt;em&gt;synthetic peptide-based serologic assays&lt;/em&gt; that exploit &lt;strong&gt;avidity&lt;/strong&gt; to replace whole antigens while enabling &lt;em&gt;low-cost diagnostics&lt;/em&gt; in resource-limited settings.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Objective:&lt;/strong&gt; To evaluate the &lt;strong&gt;diagnostic accuracy&lt;/strong&gt; of a &lt;em&gt;polymeric peptide-based ELISA&lt;/em&gt; leveraging avidity to enhance signal strength.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Method:&lt;/strong&gt; A &lt;strong&gt;15-member SARS-CoV-2 peptide library&lt;/strong&gt; corresponding to multiple epitope clusters and proteins was screened by &lt;em&gt;indirect ELISA&lt;/em&gt; using pooled sera from RT-PCR-confirmed patients. The lead peptide candidate, &lt;code&gt;S559&lt;/code&gt;, was identified and modified by &lt;em&gt;terminal cysteine-substitution&lt;/em&gt; to enable disulfide-linked polymerization. Avidity gain was quantified by comparing the apparent dissociation constant (&lt;code&gt;K&lt;sub&gt;Dapp&lt;/sub&gt;&lt;/code&gt;) of the polymerized vs. depolymerized forms, the latter achieved using &lt;code&gt;N-acetylcysteine&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;An optimized ELISA based on &lt;code&gt;S559&lt;/code&gt; was evaluated on:&lt;/p&gt;
&lt;ul&gt;
 &lt;li&gt;1,222 prospectively collected COVID-19 serum samples&lt;/li&gt;
 &lt;li&gt;218 biobanked negative controls&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Polymeric &lt;code&gt;S559&lt;/code&gt; exhibited a &lt;strong&gt;&lt;em&gt;218% avidity gain&lt;/em&gt;&lt;/strong&gt; relative to its depolymerized form, with a &lt;code&gt;K&lt;sub&gt;Dapp&lt;/sub&gt;&lt;/code&gt; of 29.26 nM&lt;sup&gt;-1&lt;/sup&gt;. Diagnostic performance of the optimized ELISA was:&lt;/p&gt;

&lt;ul&gt;
 &lt;li&gt;&lt;strong&gt;Sensitivity:&lt;/strong&gt; 83.39% (95% CI: 81.18%–85.43%)&lt;/li&gt;
 &lt;li&gt;&lt;strong&gt;Specificity:&lt;/strong&gt; 96.79% (95% CI: 93.50%–98.70%)&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Using &lt;em&gt;post hoc thresholds&lt;/em&gt; derived via the Youden Index:&lt;/p&gt;
&lt;ul&gt;
 &lt;li&gt;&lt;strong&gt;Sensitivity:&lt;/strong&gt; 95.01% (95% CI: 93.63%–96.16%)&lt;/li&gt;
 &lt;li&gt;&lt;strong&gt;Specificity:&lt;/strong&gt; 100.00% (95% CI: 98.32%–100.00%)&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt; Homomultivalent epitope presentation using polymeric &lt;code&gt;S559&lt;/code&gt; enables a &lt;em&gt;highly specific and sensitive immunoassay&lt;/em&gt; for detecting anti-SARS-CoV-2 antibodies. This method has potential utility in &lt;strong&gt;infection diagnosis&lt;/strong&gt;, &lt;strong&gt;vaccine response monitoring&lt;/strong&gt;, and &lt;strong&gt;seroepidemiologic surveillance&lt;/strong&gt;.&lt;/p&gt;

&lt;p&gt;&lt;em&gt;Contact: &lt;a href="mailto:bnaclp@gmail.com"&gt;bnaclp@gmail.com&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;