Reduced expression of AP3δ affects the stability of the AP3 complex. Western blot analysis of lysates from magnetically activated cell sorter (MACS) –purified CD8 T cells of 2 healthy controls: an AP3β3A-deficient patient and the index patient (lanes 1-4). Two separate blots are shown that used rabbit antibodies against AP3δ and AP3σ (left) and AP3β and AP3μ (right). β-actin was used as a loading control. AP3δ protein was analyzed by using 2 different antibodies^23,24  in 3 independent experiments with similar results. Lanes 5 and 6 show blots from patient PHA/IL-2 blasts retrovirally transduced with an AP3D1-expressing or empty vector analyzed in the same experiment. These cells were sorted by using fluorescence-activated cell sorting (FACS) for GFP-positive cells to enrich for successfully transduced cells.