Delayed and highly specific antibody response to nonstructural protein 1 (NS1) revealed during natural human ZIKV infection by NS1-based capture ELISA

Fuchun Zhang,Yingfen Wen,Lei Yu,Jian Wang,Xiujie Gao,Chunlin Li,Chibiao Yin,Wenxin Hong,Xia Jin,Lingzhai Zhao

doi:10.1186/s12879-018-3173-y

Abstract

BackgroundZika virus (ZIKV) had spread rapidly in the past few years in southern hemisphere where dengue virus (DENV) had caused epidemic problems for over half a century. The high degree of cross-reactivity of Envelope (E) protein specific antibody responses between ZIKV and DENV made it challenging to perform differential diagnosis between the two infections using standard ELISA method for E protein.MethodsUsing an IgG capture ELISA, we investigated the kinetics of nonstructural protein 1 (NS1) antibody response during natural ZIKV infection and the cross-reactivity to NS1 proteins using convalescent sera obtained from patients infected by either DENV or ZIKV.ResultsThe analyses of the sequential serum samples from ZIKV infected individuals showed NS1 specific Abs appeared 2 weeks later than E specific Abs. Notably, human sera from ZIKV infected individuals did not contain cross-reactivity to NS1 proteins of any of the four DENV serotypes. Furthermore, four out of five NS1-specific monoclonal antibodies (mAbs) isolated from ZIKV infected individuals did not bind to DENV NS1 proteins. Only limited amount of cross-reactivity to ZIKV NS1 was displayed in 108 DENV1 immune sera at 1:100 dilution.ConclusionsThe high degree of NS1-specific Abs in both ZIKV and DENV infection revealed here suggest that NS1-based diagnostics would significantly improve the differential diagnosis between DENV and ZIKV infections.

Highlights

Zika virus (ZIKV) had spread rapidly in the past few years in southern hemisphere where dengue virus (DENV) had caused epidemic problems for over half a century
Expression of recombinant nonstructural protein 1 (NS1) protein and establishment of capture Enzyme-linked immunosorbent assay (ELISA) To investigate the human antibody response to ZIKV NS1 protein, we first expressed the full length NS1 proteins of ZIKV and Dengue virus serotype 1 (DENV1)–4 in mammalian 293 T cells (Fig. 1a and Additional file 1) and collected the culture supernatants containing NS1 proteins, which were shown to be about 55KD as detected by the D7 tag antibody in western blot (Fig. 1b). These NS1 proteins were used to set up capture ELISA with D7 Ab pre-coated plates
Dynamics and cross-reactivity of NS1 antibody response during natural ZIKV infection To examine the dynamic changes of human NS1 antibody response at polyclonal level during the course of ZIKV infection, we measured the serum binding Abs in sequential samples from two ZIKV infected patients

Summary

Introduction

Zika virus (ZIKV) had spread rapidly in the past few years in southern hemisphere where dengue virus (DENV) had caused epidemic problems for over half a century. The high degree of cross-reactivity of Envelope (E) protein specific antibody responses between ZIKV and DENV made it challenging to perform differential diagnosis between the two infections using standard ELISA method for E protein. The preexisting DENV immune status in population combined with the risk of endemic spread of ZIKV infection, have raised the question of how to diagnosis each specific infection, and whether disease severity will be altered due to a potential antibody cross-reactivity because of the genetic and structural closeness between these two flaviviruses. The flavivirus E protein is the main target of human antibody response. It contains three domains, EDI, EDII and EDIII [10]. The high cross-reactivity between ZIKV and DENV E-specific Abs was commonly known because of the similarity of their E proteins in sequence

Methods

Results

Discussion

Conclusion