Figure 4. Three distinct patterns of proliferation and differentiation for B cells.

The two panels on the left (a,b) illustrate the quantal all-or-none stimulation seen with TLR ligation. Different average stimulation doses are illustrated by the vertical heat map (darker being stronger stimulation). Once stimulation is above a threshold, cells proceed to first and subsequent divisions. The times for division are fixed for all levels of stimulation. Stimulation does affect the number of divisions reached and therefore the initiation of cell death. LPS-stimulated cells progressively differentiate to ASC as they divide, illustrated here by the increasing intensity of green. In the right panel (c), the graded response seen for CD40 stimulation is shown. The time to first division is graded by stimulation strength, as is the total number of divisions reached. Here the proportion of cells becoming ASC per division is higher at the lower stimulation strengths, perhaps linking differentiation to time exposed to the stimulus within any single division.