Specific detection of dengue and Zika virus antibodies using envelope proteins with mutations in the conserved fusion loop

Beyene Moges,Giorgio Palù,Andres Moreira-Soto,Jan Felix Drexler,Alexandra Rockstroh,Sebastian Ulbert,Manoel Sarno,Carlos Brites,Orlando C Ferreira,Alessandro Sinigaglia,Luisa Barzon,Widuranga Kumbukgolla,Jonas Schmidt-Chanasit

doi:10.1038/emi.2017.87

Abstract

Detection of antibodies is widely used for the diagnosis of infections with arthropod-borne flaviviruses including dengue (DENV) and Zika virus (ZIKV). Due to the emergence of ZIKV in areas endemic for DENV, massive co-circulation is observed and methods to specifically diagnose these infections and differentiate them from each other are mandatory. However, serological assays for flaviviruses in general, and for DENV and ZIKV in particular, are compromised by the high degree of similarities in their proteins which can lead to cross-reacting antibodies and false-positive test results. Cross-reacting flavivirus antibodies mainly target the highly conserved fusion loop (FL) domain in the viral envelope (E-) protein, and we and others have shown previously that recombinant E-proteins bearing FL-mutations strongly reduce cross-reactivity. Here we investigate whether such mutant E-proteins can be used to specifically detect antibodies against DENV and ZIKV in an ELISA-format. IgM antibodies against DENV and ZIKV virus were detected with 100% and 94.2% specificity and 90.7% and 87.5% sensitivity, respectively. For IgG the mutant E-proteins showed cross-reactivity, which was overcome by pre-incubation of the sera with the heterologous antigen. This resulted in specificities of 97.1% and 97.9% and in sensitivities of 100% and 100% for the DENV and ZIKV antigens, respectively. Our results suggest that E-proteins bearing mutations in the FL-domain have a high potential for the development of serological DENV and ZIKV tests with high specificity.Emerging Microbes & Infections (2017) 6, e99; doi:10.1038/emi.2017.87; published online 8 November 2017

Highlights

Arthropod-transmitted flaviviruses are small, enveloped RNA viruses, which are endemic to many parts of the world
Our results suggest that fusion loop (FL)-mutant E-proteins of ZIKV and DENV can be used for a specific serological diagnosis of both infections
By using mutations within and next to the FL-domain of the E-proteins of DENV and ZIKV, we found that IgM antibodies show greatly reduced cross-reactivity and bind to the homologous antigen

Summary

Introduction

Arthropod-transmitted flaviviruses are small, enveloped RNA viruses, which are endemic to many parts of the world. They include a large number of important human pathogens, such as dengue, Zika, yellow fever, West Nile, Japanese encephalitis and tick-borne encephalitis viruses (DENV, ZIKV, YFV, WNV, JEV and TBEV, respectively).[1] On the basis of their antigenic properties, flaviviruses are divided into distinct serocomplexes, such as the JEV serocomplex (which contains JEV, WNV and others), or the DENV serocomplex (with the different dengue virus serotypes).[2] Among flaviviruses, DENV is causing the most severe impact on human health. Many of the human pathogenic flaviviruses are transmitted by the same mosquito species (especially of the genus Aedes), and areas where different flaviviruses co-circulate are increasing in number, most importantly DENV and ZIKV in South America.[9,10]

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Conclusion