Development of an anti-dengue NS1 IgG ELISA to evaluate exposure to dengue virus

Abstract

Dengue virus infection elicits immune responses to multiple viral antigens including antibodies to dengue non-structural protein 1 (NS1) which are rapidly induced and detected within days of infection. The recombinant, live, attenuated, tetravalent dengue vaccine (CYD-TDV; Sanofi Pasteur) uses the yellow fever vaccine virus as a back-bone but expresses dengue virus pre-membrane and envelop proteins. Since CYD-TDV does not express dengue NS1, we evaluated the utility of dengue NS1-specific IgG antibodies as biomarkers of dengue exposure in CYD-TDV recipients and controls. We optimized and evaluated a quantitative anti-dengue NS1 IgG enzyme-linked immunosorbent assay (ELISA). Parameters assessed included: accuracy, dilutability/linearity, precision, limit of quantitation and specificity. The assay specificity was further evaluated using Japanese Encephalitis virus, West Nile virus, Yellow Fever virus or Zika virus positive sera samples collected following confirmed infection or vaccination. Receiver-operating-characteristics (ROC) curves as well as sensitivity and specificity for discriminating previous dengue exposure were assessed using 1250 reference samples. Overall, the anti-dengue NS1 IgG ELISA was able to discriminate previous dengue exposure from non-exposure before vaccination with CYD-TDV (ROC area under the curve > 0.9). Assessment of paired samples from 2511 vaccinated participants showed high overall agreement (93%) between pre-vaccination and post-vaccination dengue serostatus classification based on the anti-dengue NS1 IgG ELISA. However, misclassification of dengue serostatus was observed after vaccination likely due to a combination of asymptomatic dengue infections, assay variability and a modest effect of CYD-TDV on the anti-dengue NS1 IgG ELISA readout.

Combination of Nonstructural Protein 1-Based Enzyme-Linked Immunosorbent Assays Can Detect and Distinguish Various Dengue Virus and Zika Virus Infections

“…Another study using a mixed DENV1-4 NS1 IgG ELISA to determine DENV immune status among Dengvaxia recipients reported high sensitivity and specificity. However, limited numbers of other flavivirus controls (4 ZIKV and 3 WNV samples) showed positivity (40), raising concerns about its practical application in regions of endemicity where multiple flaviviruses are prevalent. With Ͼ124 control samples, including naive, pZIKV, and pWNV panels, our DENV1-4 NS1 IgG ELISA showed specificity at levels to suggest it might be a useful tool to determine DENV immune status in regions of endemicity.…”

Comprehensive response to Usutu virus following first isolation in blood donors in the Friuli Venezia Giulia region of Italy: Development of recombinant NS1-based serology and sensitivity to antiviral drugs

“…The Eurimmune USUV IgG ELISA is based on the viral structural proteins and these assays suffer from broad antigenic cross-reactivity of anti-flavivirus antibodies [32]. To this end the use of secreted flavivirus NS1 as an antigen alternative to virion proteins for the detection of IgM/G has proven to provide a better level of specificity [24,[33][34][35][36][37][38]. NS1 is secreted as a glycosylated oligomer in high amounts during the viremic phase and its detection is considered a marker of infection [39].…”

A Simple Method for the Design and Development of Flavivirus NS1 Recombinant Proteins Using an In Silico Approach

“…Measurement of specific antibody responses to NS1 using IgM and IgG antibody capture enzyme-linked immunosorbent assays (MAC-and GAC-ELISAs) could provide an alternative approach for the identification of infectious flaviviruses [28][29][30]. In addition, it has been reported that anti-JEV NS1 antibodies can function as serological markers of natural infection within the vaccinated population [31,32], and anti-DENV NS1 IgG ELISA can detect previous dengue exposure prior to vaccination [33]. In particular, the detection of previous exposure and quantification of the serostatus is important prior to vaccination, as flavivirus cross-reactive antibodies may contribute to the severity of secondary flavivirus infection, owing to antibody-dependent enhancement (ADE) [34].…”