FIG 1.
Characterization of recombinant MV expressing a soluble form of the ZIKV E protein. (A) A truncated version of the ZIKV E protein gene lacking the stem-anchor region, resulting in sE, was inserted together with the prM gene preceded by the C-terminal signal peptide of the capsid (C) sequence, indicated by a black bar, into an additional transcription unit following the P gene cassette of the MVSchw genome. (B and C) ZIKV E protein expression in Vero cells was verified via immunoperoxidase monolayer assay (IPMA) (B) or Western blot analysis (C) directly comparing two clones of MV-Zika-sE encoding soluble E (MV-sE#4 and MV-sE#11) to control MVSchw virus encoding GFP (MV-GFP). The blots and fixed cells were probed as indicated. The apparent molecular weight is also indicated. (D and E) Multistep growth kinetics of the indicated recombinant MV (P4) on Vero cells at an MOI of 0.03. Shown are titers of cell-associated virus (E), as well as virus in the cell supernatant (D), of samples at the indicated time points postinfection titrated on Vero cells. Means and standard deviations of the results of three independent experiments and the lower limit of detection (LLD) (dotted lines) of 1 × 102 TCID50/ml are depicted.