The modeled expression profile of CD64 in response to B. pertussis (a) and S. aureus (b) treatments (surface fitted using 4 independent measurements). The x-axis represents time, the y-axis, exposure dose, and the z-axis, the expression level (log2) of the zero-transformed data. The surface represents the least squares fit of the expression data to the model. The correlation of the fitted to observed responses was 0.83. c, The subtraction of the two expression surfaces, delta(d,t). d, The same fitted response difference as in c, but in the from of a 2-dimensional color image and contour plot, in which a red to blue color scale represents high to low absolute difference, respectively.