Figure 5

Interaction between multiple cells. (A) The distribution of bound IL-2R, B, of a cell with m = 1, Cell1, while interacting with 9 other cells with random m values. The number of IL-2R of Cell1 was normalized by its value when there is no interaction. Δt is the time difference between the activation of Cell1 and the random ensemble. When the time delay is short (black, red), Cell1 benefits from the interaction. However, when Cell1 is activated after a longer delay (green, blue), a bi-modal distribution emerges with an additional peak around very low values of B. Even the ‘strongest’ cell can be excluded if activated too late. The volume of interaction for this graph is 5 times the volume that was used for 2 cell interaction and thus the cell density is the same. The m values in each ensemble were randomly pulled out of a uniform distribution. Each distribution is the result of 10,000 runs. (B-E) The effect of ensemble composition on the response of Cell1. As the mean TCR strength of the competitors is larger (B, C) the amount of IL-2R of cell1 decreases. If the delay is long, exclusion may occur only if the mean m of the competing group is high enough (above ~ 0.5). On the top of it, the maximal competitor has to be strong enough (above ~ 0.75) for exclusion to occur (D, E).