CCR8 promotes medullary enrichment of CD4SP thymocytes.

<p>(A) A maximum intensity projection of <i>Ccr8</i>^<i>+/+</i> (pink) and <i>Ccr8</i>^<i>-/-</i> (green) CD4SP thymocytes in live pCX-EGFP (cyan) thymic slices, from 2-photon fluorescence microscopy images. The boundary between cortex (C) and medulla (M) is indicated with a dashed line. Bar 50μm; acquired with a 20X objective. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0200765#pone.0200765.s005" target="_blank">S1 Movie</a>. (B) The density of cells (cells/μm²) in the medulla and in the cortex was calculated from images as in (A), and enrichment of CD4SP cells in the medulla was determined as a ratio of medullary to cortical densities. CD4SP medullary enrichment was calculated from three independent imaging experiments, with a total of 11 slices analyzed. *<i>p</i> < 0.05 (paired Student’s <i>t</i>-test).