Comparable Accuracies of Nonstructural Protein 1- and Envelope Protein-Based Enzyme-Linked Immunosorbent Assays in Detecting Anti-Dengue Immunoglobulin G Antibodies.

Jedhan Ucat Galula,Roland Remenyi,Gielenny M Salem,Raul V Destura,Day-Yu Chao

doi:10.3390/diagnostics11050741

Jedhan Ucat Galula, Roland Remenyi + Show 3 more

Open Access

https://doi.org/10.3390/diagnostics11050741

Copy DOI

Abstract

Background: Dengue virus (DENV) infection remains a global public health concern. Enzyme-linked immunosorbent assays (ELISAs), which detect antibodies targeting the envelope (E) protein of DENV, serve as the front-line serological test for presumptive dengue diagnosis. Very few studies have determined the serostatus by detecting antibodies targeting the nonstructural protein 1 (NS1), which can function as diagnostic biomarkers to distinguish natural immunity from vaccine-induced immunity. Methods: We used community-acquired human serum specimens, with the serostatus confirmed by focus reduction microneutralization test (FRμNT), to evaluate the diagnostic performances of two NS1-based ELISA methods, namely, immunoglobulin G antibody-capture ELISA (NS1 GAC–ELISA) and indirect NS1 IgG ELISA, and compared the results with an E-based virus-like particle (VLP) GAC–ELISA. Results: NS1-based methods had comparable accuracies as VLP GAC–ELISA. Although the sensitivity in detecting anti-NS1 IgM was poor, indirect NS1 IgG ELISA showed similar limits of detection (~1–2 ng/mL) as NS1 GAC–ELISA in detecting anti-NS1 IgG. Combining the results from two or more tests as a composite reference standard can determine the DENV serostatus with a specificity reaching 100%. Conclusion: NS1-based ELISAs have comparable accuracies as VLP GAC–ELISA in determining dengue serostatus, which could effectively assist clinicians during assessments of vaccine eligibility.

Highlights

Flaviviruses of the family Flaviviridae are associated with several arthropod-borne diseases that are divided into different serological complexes, including members of the tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), Japanese encephalitis virus (JEV), Zika virus (ZIKV), and dengue virus (DENV) serocomplexes based on the antibodies against the immunodominant envelope (E) protein [1,2]
Upon reviewing the relevant literature, we found that the commercially available nonstructural protein 1 (NS1) proteins from Native Antigen Company are widely used in several NS1 protein-related studies and were used as the standard antigens in this study to ensure the quality of our in-house-produced NS1 proteins
Upon visualization by Coomassie blue staining of the nonreducing SDS–PAGE (Figure 1B), the in-house and commercial NS1 proteins appeared to exist as heterogeneous conformations ranging from monomers, dimers, oligomers, and as protein aggregates that were not able to migrate into the resolving gel due to their large size

Summary

Introduction

Flaviviruses of the family Flaviviridae are associated with several arthropod-borne diseases that are divided into different serological complexes, including members of the tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), Japanese encephalitis virus (JEV), Zika virus (ZIKV), and dengue virus (DENV) serocomplexes based on the antibodies against the immunodominant envelope (E) protein [1,2]. Commercial vaccines for human use are only available for TBEV (FSME-IMMUN® , Encepur® , TBE-Moscow® , and EnceVir® ), YFV (17D and YF-Vax® ), JEV (IXIARO® and IMOJEV® ), and DENV (Dengvaxia® ), despite the steady expansion and circulation of flaviviruses worldwide [7,8,9]. It is imperative to establish a reliable serological assay that can differentiate natural immunity from vaccine-induced immunity. This serological differentiation is essential because the demonstration of natural infection in vaccinated populations is crucial for monitoring and evaluating vaccine efficacy and safety

Objectives

Methods

Results

Conclusion