NS1-based ELISA test efficiently detects dengue infections without cross-reactivity with Zika virus.

Objectives: The aim of this study was to achieve greater specificity of dengue virus (DENV) serological tests based on a recombinant antigen derived from non-structural protein 1 (ΔNS1) with regard to cross-reactive Zika virus (ZIKV) anti-NS1 antibody responses. This is of relevance in endemic regions for the serological discrimination of both DENV and ZIKV, such as Brazil and other tropical countries.

Methods: The ΔNS1 proteins were obtained as recombinant antigens and were evaluated as solid-phase-bound antigens in the ELISA test to detect anti-NS1 IgG antibodies. The performance of the ∆NS1-based DENV IgG ELISA was assessed with both mouse and human serum samples previously exposed to DENV or ZIKV.

Results: The ∆NS1-based DENV IgG ELISA detected anti-DENV NS1 IgG without cross-reactivity with ZIKV-positive serum samples. The sensitivity and specificity of the assay determined using samples previously characterized by real-time PCR (qRT-PCR) or plaque reduction neutralization assay (PRNT) were 82% and 93%, respectively.

Conclusion: The ∆NS1-based DENV IgG ELISA conferred enhanced diagnostic specificity for anti-DENV serological tests and may be particularly useful for serological analyses in endemic regions for both DENV and ZIKV transmission.