Developmental regulation of the intrathymic T cell precursor population

B. Adkins

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


The maturation potential of CD4-8- thymocytes purified from mice of different developmental ages was examined in vivo after intrathymic injection. As previously reported, 14-day fetal CD4-8- thymocytes produced fewer CD4+ than CD8+ progeny in peripheral lymphoid tissues, resulting in a CD4+:CD8+ ratio of ≤1.0. In contrast, adult CD4-8- thymocytes generated CD4+ or CD8+ peripheral progeny in the proportions found in the normal adult animal (CD4+:CD8+ = 2 to 3). Here we have shown that CD4-8- precursor cells from the 17-day fetal thymus also produced peripheral lymphocytes with low CD4+:CD8+ ratios. Precursors from full term fetuses produced slightly higher CD4+:CD8+ ratios (1.1-1.6) and precursors from animals three to 4 days post-birth achieved CD4+:CD8+ ratios intermediate between those produced by fetal and adult CD4-8- thymocytes. Parallel changes in the production of αβ TCR+ peripheral progeny were observed. Fetal CD4-8- thymocytes generated fewer αβ TCR+ progeny than did adult CD4-8- thymocytes. However, peripheral lymphocytes arising from either fetal or adult thymic precursors showed similar proportions of γδ TCR+ cells. The same pattern of progeny was observed when fetal CD4-8- thymocytes matured in an adult or in a fetal thymic stromal environment. In contrast to fetal thymic precursors, fetal liver T cell precursors resembled adult CD4-8- thymocytes by all parameters measured. These results suggest that fetal thymic precursors are intrinsically different from both adult CD4-8- thymocytes and fetal liver T cell precursors. Moreover, they lead to the hypothesis that the composition of the peripheral T cell compartment is developmentally regulated by the types of precursors found in the thymus. A model is proposed in which migration of adult-like precursors from the fetal liver to the thymus approximately at birth triggers a transition from the fetal to the adult stages of intrathymic T cell differentiation.

Original languageEnglish (US)
Pages (from-to)1387-1393
Number of pages7
JournalJournal of Immunology
Issue number5
StatePublished - Jan 1 1991

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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