Characterization of recombinant YF 17D viruses. A) Replicative kinetics in Vero cells of recombinant viruses. YF 17D/NS2B3/Tc (open triangles) and YF 17D/E200/Tc (black squares), control YF 17D/E200T3 (dark gray discontinuous circles) and YF 17DD (light gray complete circles). Each time point represents the average titer obtained from three separate experiments with the respective standard deviations. No statistically significant differences were found. B) Plaque morphology of YF 17DD, 17D/NS2B3/Tc and YF17D/E200/Tc.