We are left then with two experimental measures -the viral titer growth rate and the plaque velocity -whose values may depend on three unknown infection kinetics parameters: the infecting time, t inf ; the latent infection period, t L ; and the infectious lifespan of a cell, t I . To determine how each of these parameters affect the infection dynamics, we varied each individually about a base value and measured the effect on the simulated experimental quantities ( Figures 5A and 5B ).