Fig. 5. Rare, activating cells exposed to weak agonist exhibit correlated binding events.
(A to B) Representative nearest-neighbor distance analysis for the proximity between pMHC-TCR binding events on T cells stimulated with MCC pMHC (A) or T102S (B) at comparable densities. For a given pMHC-TCR binding event (orange circle), the distance to its nearest neighbor (yellow line) at the same time point (left) or within a time window (right) was determined from analysis of the data in Fig. 4. Scale bars, 3 μm. (C to H) Nearest-neighbor distance distribution of pMHC-TCR binding events that occurred concurrently (C to E) or within a 30-s time window (F to H) in response to threshold MCC pMHC density (C and F), threshold T102S density (D and G), and low T102S density (E and H) stimulation. Gray areas indicate the fraction of nearest-neighbor separations up to 2 mm in cells that activated NFAT (Act.; filled bars) and those that did not (Nonact.; empty bars) from the analysis of the data from Fig. 4.