Fig. 4.

The potency of pMHC is a greater influence on T-DC interactions than pMHC density after controlling for proliferation. 5C.C7 Ub-GFP T cells were imaged using two-photon microscopy on intact LN 15 hours after injection of the indicated peptide (High: 2μg, Low: 0.2μg). (A) Cumulative frequency plot for velocity is shown from one representative experiment of three. (B) Representative images are shown with circles indicating 5C.C7 interacting with CD11c-YFP DC (solid line indicates ≥300 sec). (C) Tabulated duration of interactions and (D) percent of time in contact with DC are shown. Contact duration was analyzed for two of three representative two-photon experiments. 5C.C7 surface expression of CD69 and CD62L (E) was assessed in LN cells isolated at the time of imaging. Shaded histograms represent the no-peptide control.