Frequency of T-cell progenitors in nude mice.
The hypothesis that prothymocytes are distinct from and regulated independently of multilineage hemopoietic progenitors was tested by enumeration of these two cell populations in normal versus congenitally athymic (nude) mice. The absence of a thymus and of peripheral T cells in nude mice had no effect on the frequency of either multilineage progenitors (day 12 CFU-S) or prothymocytes (CFU-T), suggesting that there is no feedback regulation of CFU-T frequency. Thymus seeding from the bone marrow is therefore likely to be regulated by the availability of niches for prothymocyte maturation, rather than by feedback control of prothymocyte production.
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Immunobiology Section, Yale Medical School, New Haven, Connecticut 06510, USA.
D000818:Animals; D001853:Bone Marrow / Q000033:anatomy & histology / Q000276:immunology; D002454:Cell Differentiation; D019070:Cell Lineage; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D013950:Thymus Gland / Q000033:anatomy & histology / Q000276:immunology*