Characterization of CCR9 expression on different thymocyte subsets.

(A) Thymocytes were stained in 3-color assays with the affinity-purified rabbit antimouse CCR9 pAb K629, which was followed by anti-CD4, anti-CD8, and antirabbit Ig-FITC (bold line). Numbered histograms show the CCR9 expression of the corresponding gated cell subpopulations indicated in the CD4/CD8 plot. Control stainings with an irrelevant rabbit antimouse serum are also shown (dotted line). (B) Flow cytometry analysis of thymocytes that have migrated in response to 300 nM CCL25 or control buffer. Thymocytes in the lower chamber of Transwell inserts were counted and stained with anti-CD4 and anti-CD8 pAbs. The percentage of cells in each subset is shown (upper right); analysis of input thymocytes is also shown. Representative results are shown of more than 10 independent experiments performed.