Removing Negative Impacts from Inevitable Nonreproducible and Nonspecific Antibody–Probe Interactions in Viral Serology

Serological
assays are indispensable tools in public health. Presently
deployed serological assays, however, largely overlook research progress
made in the last two decades that jeopardizes the conceptual foundation
of these assays, i.e., antibody (Ab) specificity. Challenges to traditional
understanding of Ab specificity include Ab polyspecificity and most
recently nonreproducible Ab–probe interactions (NRIs). Here,
using SARS-CoV-2 and four common livestock viruses as a test bed,
we developed a new serological platform that integrates recent understanding
about Ab specificity. We first demonstrate that the response rate
(RR) from a large-sized serum pool (∼100) is not affected by
NRIs or by nonspecific Ab–probe interactions (NSIs), so RR
can be incorporated into the diagnostic probe selection process. We
subsequently used multiple probes (configured as a “protein
peptide hybrid microarray”, PPHM) to generate a digital microarray
index (DMI) and finally demonstrated that DMI-based analysis yields
an extremely robust probabilistic trend that enables accurate diagnosis
of viral infection that overcomes multiple negative impacts exerted
by NSI/NRI. Thus, our study with SARS-CoV-2 confirms that the PPHM-RR-DMI
platform enables very rapid development of serological assays that
outperform traditional assays (for both sensitivity and specificity)
and supports that the platform is extendable to other viruses.