Development of T cell precursor activity in the murine fetal liver.
The generation of T cell precursors in the liver of murine embryos was studied. The total number of T cell precursors in the liver was measured in thymic organ cultures by a limiting dilution assay. Sixty T cell precursors were detected in the liver at day 11 of gestation. By day 12 the number of precursors showed a 20-fold increase, half of which could be explained by in situ proliferation as ascertained by a fetal liver organ culture assay. By day 13 a further 2-3-fold increase was observed. Whereas the number of total liver cells continued to increase, that of T cell precursors declined in the following days, suggesting a massive exit of these cells after day 13. The capacity to generate a TCRB repertoire in the cells was evaluated by a PCR assay. T cell precursors in day 11 fetal liver developed a TCRB repertoire at day 8 of culture. The cells from days 12-15 developed an identically diverse repertoire by day 6, suggesting that day 11 precursors are more immature than those of later days. A mechanism for yielding a single wave of T cell precursors in the fetal liver is discussed with a proposed model.
Ema
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H
INSERM U227, Département d'Immunologie, Institut Pasteur, Paris, France.
Douagi
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I
Cumano
A
A
Kourilsky
P
P
D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D005314:Embryonic and Fetal Development / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D008099:Liver / Q000166:cytology* / Q000196:embryology / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
D016693:Receptors, Antigen, T-Cell, alpha-beta