Fig 1.
Infection parameters definition.
Virus growth kinetics in C6/36 cell line (A). Zika virus infection in Huh 7.5 cell line with different MOIs (ranging from 0.001 to 1). Dashed line indicates 70% of infection (B). The data presented are the average results of three independent experiments.
Fig 2.
Fluorescent neutralization assay setting definition.
Representative image of negative and positive infection controls (A). Assay overview of serial dilution (1/20 to 1/43740) of a negative sample (26885) and two positive samples (LRV/16 1306 and LRV/16 1260) (B). Curve fitting of results and calculation of neutralization titer that inhibit 90% of viral infection (NT90) (C).
Fig 3.
Neutralization tests comparison.
Neutralization titers obtained from PRNT or fluorescent neutralization test are compared. A correlation of R = 0.88 was obtained (P = 0.0003).
Fig 4.
ZIKV Fluorescent neutralization test validation.
A total of 226 serum samples, among then negative and positive for flavivirus and non-flavivirus infections were examined. The neutralization titers that inhibit 90% of viral infection (NT90) are shown in the graph. Other infections: Leptospirosis, CMV, EBV, Hantavirus, Toxoplasmosis, VDRL. Dashed lines represent the test cut off: negative when NT90 <10, inconclusive when NT90 ≥10 and <20, and positive when NT90 ≥20. Symbols in blue indicate paired samples.
Table 1.
Panel of serum samples used for the new ZIKV fluorescent neutralization test validation.
Table 2.
Characterization of Zika positive serum samples.
Fig 5.
ZIKV neutralization test with paired samples.
Second collections were performed from 3 to 6 months after the first one. Dashed lines represent test cut off: negative when NT90 <10, inconclusive when NT90 ≥10 and <20, and positive when NT90 ≥20.
Table 3.
Panel of DENV IgM positive samples.
Table 4.
Comparison of Zika MAC-ELISA and the new ZIKV fluorescent neutralization test with IgM DENV positive samples.
Table 5.
DENV fluorescent neutralization test results for sera of patients with proven DENV infection.