Fig 1.
Results of the multiplex NS1 IgG MIA tested with different primary flavivirus infection and naïve panels.
(a-f) Convalescent-phase and post-convalescent-phase samples of pDENV1 (b), pDENV2 (c), pDENV3 (d), pZIKV (e) and pWNV (f) panels as well as flavivirus naïve (a) panel were tested. (g) Detection rates of different NS1 IgG MIA by each panel. Data are the means of two separate experiments (each in duplicate). Dashed lines indicate cutoff rMFI; horizontal lines the means of each NS1 in panel a.
Fig 2.
Results of the multiplex NS1 IgG MIA tested with repeated flavivirus infection panels.
(a-d) These include sDENV panel at the convalescent (a) and post-convalescent (c) phases and ZIKVwprDENV panel at the convalescent (b) and post-convalescent (d) phases. Data are the means of two experiments (each in duplicate). Dashed lines indicate cutoff rMFI. (e-h) The rMFI ratio of ZIKV NS1 to DENV1 NS1 for the convalescent-phase (e) and post-convalescent-phase (g) samples, and the rMFI ratio of ZIKV NS1 to DENV2 NS1 for the convalescent-phase (f) and post-convalescent-phase (h) samples were shown. Data are the means of two experiments (each in duplicate). Dashed lines indicate cutoff rMFI ratio (0.62). The two-tailed Mann-Whitney test was used to compare two groups.
Fig 3.
Comparison between NS1 IgG MIA and ELISA for pZIKV and pDENV1 panels.
(a-d) The results of ZIKV NS1 IgG ELISA (a) and MIA (b) for convalescent- and post-convalescent-phase samples of pZIKV panel. Relationship between rOD and rMFI values for the convalescent-phase (c) and post-convalescent-phase (d) samples. (e-h) The results of DENV1 NS1 IgG ELISA (e) and MIA (f) for convalescent- and post-convalescent-phase samples of pDENV1 panel. Relationship between rOD and rMFI values for the convalescent-phase (g) and post-convalescent-phase (h) samples. Data are the means of two experiments (each in duplicate). Dashed lines indicate cutoff rOD or rMFI. The two-tailed Spearman correlation test was performed; r, correlation coefficient.
Fig 4.
Comparison between NS1 IgG MIA and ELISA for ZIKVwprDENV panel.
(a-d) The results of ZIKV NS1 IgG ELISA (a) and MIA (b) for convalescent- and post-convalescent-phase samples. Relationship between rOD and rMFI values for the convalescent-phase (c) and post-convalescent-phase (d) samples. Data are the means of two experiments (each in duplicate). Dashed lines indicate cutoff rOD or rMFI. The two-tailed Spearman correlation test was performed; r, correlation coefficient. (e) Summary of the relationship between rOD and rMFI values of different NS1 IgG ELISAs and MIAs for the convalescent-phase and post-convalescent-phase samples of ZIKVwprDENV panel.
Table 1.
Results of NS1 IgG MIA in different serum/plasma panels.
Table 2.
Sensitivity and specificity of different NS1 IgG MIA a.
Fig 5.
Proposed algorithm of using multiplex NS1 IgG MIA to distinguish three flavivirus infections.
Based on positivity to NS1 proteins of three serocomplexes (DENV [DENV1, 2, 3 or 4], ZIKV and WNV NS1), the samples that were negative to all NS1 proteins or positive to NS1 protein of one serocomplex (DENV, ZIKV or WNV) could be flavivirus naïve or primary DENV, pZIKV or pWNV infection. For samples that were positive to NS1 proteins of two or more serocomplexes, the rMFI ratio of ZIKV NS1 to DENV1 or DENV2 NS1 was calculated to distinguish sDENV and ZIKVwprDENV infections.