Apoptosis assays

Apoptosis induction was measured using the Annexin V and propidium iodide staining kit from BioLegend. Cells were stained for surface markers, then washed and stained in calcium-containing binding buffer according to the manufacturer’s directions. To measure Caspase 3/7 activation, cells were stained for surface markers, then stained for caspase-3 and -7 activation according to the Vybrant FAM caspase-3 and -7 activation kit manufacturer’s instructions. Human LCH lesion apoptosis was measured using the Annexin V & Dead Cell Assay kit (Millipore) on a Muse Cell Analyzer (Millipore) according to the manufacturer’s recommendation. In brief, 100 µl of cells in suspension was incubated with 100 μl Muse Annexin V & Dead Cell Reagent for 20 min at room temperature before being analyzed on the Muse Cell Analyzer.