Fig. 4: CD2 stabilizes close contacts, enhancing antigen detection.

a, b Image-based analysis of J8-GECI cells on an SLB2 presenting pMHC^null ± pMHC^9V-lo. a CD58 accumulation occurs at close contacts formed by J8-GECI cells. The min/max normalized intensity line profile was taken along the direction of the white arrow and indicates CD58 accumulation at close contacts. The kymograph indicates persistence of CD58 accumulation spots/close contacts. See Supplementary Movie 12. Images are representative of J8-GECI cells on n = 3 independent SLBs. b Engaged ICAM-1 is excluded from close contacts formed by J8-GECI cells. The min/max normalized intensity line profile was taken along the direction of the white arrow and indicates ICAM-1 exclusion from close contacts. The kymograph indicates persistent exclusion of ICAM-1 from close contacts. See Supplementary Movie 14. Images are representative of J8-GECI cells on n = 3 independent SLBs. c–e Close-contact analysis for J8-GECI cells interacting with an SLB2, SLB2ΔCD58, or SLB2ΔICAM-1 presenting pMHC^null; n = 34 (SLB2, the same SLBs as in Fig. 3b–e), 14 (ΔCD58, from 4 SLBs), and 8 (ΔICAM-1, from 4 SLBs) cells. See Supplementary Movies 5, 17, and 19. c Cumulative distribution of the searching to scanning stage transition for cells on the indicated SLBs. The analysis uses data for both signaling and non-signaling cells. Plotted is the cumulative distribution function of the Kaplan–Meier estimator with the exponential Greenwood confidence interval. Data were examined using a pairwise log-rank test, which indicated that there were no significant differences. d Mean glycocalyx exclusion (i.e. contact tightness) at close contacts during the scanning stage for each cell. e Mean close-contact area during the scanning stage for each cell. The analysis uses the same cells as in (d). In d and e, conditions were compared using the pairwise Mann–Whitney U test. The p values are shown. The boxplots indicate the quartiles with a line at the median. Whiskers extend to points that lie within 1.5 IQRs of the lower and upper quartile. f–h Same analysis as in (c–e) using human primary CD8⁺ T cells; n = 28 (SLB2, the same SLBs as in Fig. 3f–i), 8 (ΔCD58, from 3 SLBs), and 18 (ΔICAM-1, from 3 SLBs) cells. See Supplementary Movies 7, 18, and 20. In f, a pairwise log-rank test indicated that there were no significant differences. i Fraction of J8-GECI cells that signal. Shown is the mean ± S.D. of n = 4 SLBs per condition with ≥257 cells analyzed per SLB. SLB2 data (blue bars) and SLB2Δglycocalyx (gray bars) were compared with a one-way ANOVA with Dunnett correction using data for the 'intact' SLBs, i.e., SLB2s with and without glycocalyces, as the control groups. j Displacement tracks. Each dot/line represents a single J8-GECI cell tracked for up to 10 min, exploiting the currents generated by adding cells to the SLBs to probe the adhesiveness of the different SLBs. Data are from the same experiment as in (i). k The time taken for 50% of J8-GECI cells to adhere to the SLBs. SLB2 data (blue bars) and SLB2Δglycocalyx (gray bars) were compared separately with a one-way Kruskal–Wallis test with Dunn’s correction using data for the intact SLBs as the control groups. Data are from the same experiment as in (i). Source data are provided in the Source data file.