Extended Data Fig. 5: Schematic of T cell migration assay.

Culture medium with or without supplementation with the natural CXCR4 ligand SDF-1-α was placed in the bottom chamber of a trans-well and CD4+ T cells (WT or CXCR4 KO) were added into the top chamber. After three hours, the absolute number of cells in the bottom chamber was quantified by flow cytometry using BD Trucount™ Tubes (schematic created with BioRender.com).