Figure 7. Two patterns for heterogeneity in the population.

In (a), the quantal response of CpG and LPS stimulation is illustrated. For a high- and low-stimulation level (Ave), the actual graded variation in signalling in the population is shown (Pop). This gradation leads to half the cells falling below the threshold for proliferation in the lower stimulation dose. However, for all cells above the threshold, the times to divide show a similar range of variation, unaffected by stimulation dose, or ranking in population sensitivity. (b) The graded response to CD40 stimulation. Here the times to divide are proportional to the stimulation level, whether altered by concentration of ligand or inherent sensitivity in the population.