Chemokines and lymphopoiesis in human thymus

Distinct and redundant chemokines are responsible for organizing the extrao rdinarily diverse thymocyte populations into discrete microenvironments, fr om the arrival of immature precursors in the thymus to the migration of dif ferent mature cell types to the periphery. We propose that, by selectively mobilizing cells, chemokines can sort positively selected cells from negati vely selected cells, and that chemokines make distinctions among CD8(+) sub populations that previously have not been recognized.