Preventative Vaccines for Zika Virus Outbreak: Preliminary Evaluation

Kim, Eun; Erdos, Geza; Huang, Shaohua; Kenniston, Thomas; Falo, Louis D.; Gambotto, Andrea

To determine the plaque reduction neutralizing titer at week 6, 60 μl of the pooled sera or 30 μl of each mouse sera was diluted in twofold serial dilutions (from 1/16 to 1/516 or from 1/32 to 1/1024) and incubated with 100 pfu of ZIKV DAKAR41542 in 100 μl of serum-free media at 37°C for 1 h and subsequently added to a Vero cell monolayer at a density of 5 × 10 4 cells grown in six-well tissue culture plates and further incubated at 37°C for 1 h. After incubation, the inoculant was removed, the semisolid media was added, and the plates were incubated for an additional five days. Titers were expressed as the reciprocal of the highest serum dilution still giving a 50% reduction in plaque number (PRNT 50 ) relative to samples incubated with pre-immunized control pooled sera.