Increased cross-presentation in Rab27a^−/− mice in vivo. CFSE-labeled P14 CD8 T cells were transferred to LCMV-infected control B6, Stx11^−/−, Rab27a^−/−, and Prf1^−/− mice. The figure shows representative histograms of CFSE staining in P14 cells 3 days after transfer (right panel) and the proportion of P14 cells having divided between 0 and 5 times (black bars) or more than 5 times (white bars). Graphs represent the mean ± SD value from 2 independent experiments with 3 mice in each group. *P < .05. **P < .01. ***P < .001.