Designing and expression of novel recombinant fusion protein for efficient antigen screening of SARS-CoV-2

TL;DR

This study developed a new fusion protein-based rapid test for SARS-CoV-2 that is highly sensitive and specific for detecting both wild-type and variant strains.

Contribution

A novel recombinant fusion protein was designed and used to create a rapid antigen assay with high diagnostic accuracy.

Findings

The developed assay showed 96.51% sensitivity and 100% specificity in testing 840 samples.

The assay can detect SARS-CoV-2 wild-type and variants of concern in real-time.

The fusion protein was constructed using B cell epitopes from three key SARS-CoV-2 structural proteins.

Abstract

Corona virus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), claimed millions globally. After the report of the first incidence of the virus, variants emerged with each posing a unique threat than its predecessors. Though many advanced diagnostic assays like real-time PCR are available for screening of SARS-CoV-2, their applications are being hindered because of accessibility and cost. With the advent of rapid assays for antigenic screening of SARS-CoV-2 made diagnostics far easy as the assays are rapid, cost-effective and can be used at point-of-care settings. In the present study, a fusion construct was made utilising highly immunogenic B cell epitopes from the three important structural proteins of SARS-CoV-2. The protein was expressed; purified capture mAbs generated and rapid antigen assay was developed. Eight hundred and forty nasopharyngeal swab samples were screened for the evaluation of the developed assay which showed 37.14% positivity, 96.51% and 100% sensitivity and specificity respectively. The assay developed was supposed to identify SARS-CoV-2 wild-type as well as variants of concern and variants of importance in real-time conditions.

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