Figure 4. Single-step growth curves of parental and chimeric viruses.

HEp-2c cells were infected with the indicated viruses, at a multiplicity of infection of 25 TCID₅₀ per cell, and were incubated at 37.0°C (curves A and B) or 40.2°C (curves C). Viruses were harvested at various time points, and titrated. Standard errors of the mean of different samples are represented as error bars.