ISSN:
1432-0878
Keywords:
Thymus
;
CD4-
;
CD8-
;
thymocyte
;
Thymic hematopoietic precursors
;
Cytokines
;
Ultrastructure
;
Mouse (DBA/2, H-2d)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary We have previously shown that the interaction of thymocytes with thymic accessory cells (macrophages and/or interdigitating cells) is one of the factors required for thymocyte activation. Precursors of both thymic accessory cell and thymocytes are included in the CD4- CD8- Mac-1- Ia- subpopulation, and their respective maturation and/or activation may be modulated by granulocyte-macrophage colony-stimulating factor, interleukin 1 and interleukin 2. When CD4- CD8- thymic cells are activated with granulocyte-macrophage colony-stimulating factor plus interleukin 2, both macrophages and interdigitating-like cells are present, as shown by electron microscopy. When activated with interleukin 1 plus interleukin 2, the interdigitating-like cells is the only accessory cell present. In both culture conditions, large clusters are formed between interdigitating cells and lymphoid cells. These results have led us to propose two-step signals for thymocyte proliferation: first, the maturation of macrophages under granulocyte-macrophage colony-stimulating factor control and the production of interleukin 1, and secondly, the maturation of interdigitating cells under interleukin 1 control, their clustering with thymocytes which are then activated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00313976
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