CD11b+ CD11c+ dendritic cells were enriched from WT or Rab39a KO spleens via magnetic negative selection. Cells were fed with 3 µm magnetic beads conjugated to pHrodo. After 4 hours, cells were harvested for flow cytometry to measure fluorescence of eaten beads due to phagosomal pH. For analysis, the background fluorescence of unstained beads was subtracted from the resulting gMFI and the fold change (dox/no dox) was calculated. Shown are three independent experiments with error bars indicating the SD. p values were calculated using two-tailed ratio-paired Student's t-test. 