Attenuated immune synapse formation in Rras^−/− DCs. (A) Time-lapse confocal images at different time points are shown, illustrating an example of a synapse between a mature Rras^+/+ or Rras^−/− DCs with a naive T cell. White arrows indicate DC protrusions. DCs and T cells (T) are indicated. (B) The percentage of DC–T-cell synapses were quantified (n > 40 for each genotype) as described in “Microscopy.” (C) The duration (minutes) of T-cell synapses (n = 41) with either WT- or KO-activated DCs was quantified. ***P < .0005. Bars represent median.