CTLs exhibit random walk motility in the exocrine pancreas.
(A–E) Images from time-lapse sequences with tracked CTLs in magenta. Green clusters represent β cell mass. Tracks identify past 5 cell positions. Only cells that were tracked in 5 consecutive frames were included for analysis. C corresponds to Supplemental Video 6 and E with Supplemental Video 7. (F; corresponds to Supplemental Video 8) Analogous setup and analysis but using in vivo peptide/ adjuvant activation (ref. 31). Red lines show linear regression plot. (G) CTL stratification strategy for chemotaxis analysis according to distance from islet centroid. Red arrows represent net CTL displacement, green is isosurfaced islet contour from which centroid position was derived, and black lines represent stratification groups. (H) Net displacement relative to islet centroid, categorized according to initial position from centroid (μm). (I) Plot of track straightness across stratified CTL. (J) Comparison of track straightness between CTLs that display net inward versus outward movement relative to the islet centroid. H–J represent pooled data from 3 individual time sequences; no significant differences were found using 1-way ANOVA. Dimensions: A, w/h = 0.91/d = 6/z = 10; B, w/h = 1.52/d = 6/z = 24; C, w/h = 0.52/d = 6/z = 17; D, w/h = 0.80/d = 6/z = 15; E, w/h = 0.27/d = 5/z = 24; F, w/h = 0.69/d = 6/z = 14; t = 30 s for all series. Graphs show means ± SEM. Scale bars: 50 μm (C–G); 100 μm (A and B).