Chemotactic preferences of SDF-1 and CKβ-11/MIP-3β/ELC for thymocyte subsets. Effects on total thymocytes (A), CD4⁺ SP (B), DP (C), DN (D), and CD8⁺ SP (E) cells are shown. Thymocyte isolation and chemotaxis assays were performed as described in the Materials and Methods. Thymocytes depleted of non-T cells were used as input cells for chemotaxis. Numbers of cells migrating to the lower chamber were expressed as the percentage of input thymocytes in the upper chamber at the start time of chemotaxis. Data are expressed as the mean (±difference) of the percentage of cell migration obtained from duplicated experiments and are representative of 5 independent experiments. *Significant differences (P < .05) from background migration.