D. Dunon et al., RENEWAL OF THYMOCYTE PROGENITORS AND EMIGRATION OF THYMOCYTES DURING AVIAN DEVELOPMENT, Developmental and comparative immunology, 22(3), 1998, pp. 279-287
The avian thymus is colonized by three waves of hemopoietic progenitor
s during embryogenesis, An in vivo thymus reconstitution assay based o
n intrathymic injection of irradiated chicks showed that cells of para
-aortic foci were able to differentiate into T lymphocytes, confirming
their putative role in the first wave of thymus colonization. This as
say was also used to detect and to characterize T cell progenitors fro
m the bone marrow which are involved in the second and third wave of t
hymus colonization. In the bone marrow, progenitors that differentiate
d into T cells were found in a subpopulation that expressed the molecu
les HEMCAM, c-kit and c128, Engraftment of thymus lobes into thymectom
ized young chick recipients showed that T cell progenitors are replace
d in the thymus by subsequent waves of progenitors after hatching, Fin
ally, analysis of thymocyte differentiation suggested that gamma delta
and alpha beta T cells migrate from the thymus to the periphery in al
ternating waves. (C) 1998 Elsevier Science Ltd. All rights reserved.