Fig. 4.

T cells generate traction forces through TCR–pMHC. (A) Primary CD4⁺ T cell from mouse expressing the 5C.C7 transgenic TCR (cyan, visualized using α-CD45 Fabs) on a pillar array coated with species-appropriate α-CD3 antibody (red); α-CD28 is included in the cell culture media. Scale bar: 2 µm and 500 pN (for forces indicated as arrows). (B) Average traction force and number of underlying pillars for cells on surfaces presenting α-CD3 antibody or MCC-loaded I-Ek MHC to target the TCR complex (TCR cplx). CD28 was applied either in solution (sol’n) or coadsorbed onto the pillar. Data are mean ± SD, representing 10–15 cells per condition, and were analyzed using ANOVA and Tukey methods, α = 0.05. Data of force per pillar were not statistically different by ANOVA; grouping overbars are omitted. For data of pillar number, the red overbars group conditions that were not significantly different.