Embryonic mouse thymus development: stem cell entry and differentiation

The entry and subsequent division and differentiation of blood-borne stem cells within the embryonic thymus has been studied in a system where the inflowing cells were either chromosomally or antigenically marked. H-2 positive stem cells enter the thymus within 5 days of grafting but may wait for up to 14 days before proliferating to give rise to Thy-1 positive thymocytes.