Are the Il-2 Receptors Expressed in the Murine Fetal Thymus Functional?

Juan Carlos ZúNiga-PflüCker, Dan L. Longo, Ada M. Kruisbeek, Kendall A. Smith, Lucio Tentori, Drew M. Pardoll

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


It is well established that the majority of murine fetal thymocytes (day 15 of gestation) express receptors for interleukin 2 (IL-2), but the functional significance of these IL-2 receptors (IL-2Rs) is not clear. In situ hybridization data show a developmentally regulated expression of IL-2 and IL-2R mRNA. IL-2 binding studies were performed on fetal thymocytes and the results show the presence of both high (kD = 20 pM) and low (kD =10 nM) affinity IL-2Rs. These IL-2Rs are indeed functional: intact fetal thymic lobes (but not cell suspensions) cultured in IL-2 exhibited an in vitro proliferative response at 20 pM of IL-2, corresponding with the presence of a functional high-affinity IL-2R on fetal thymocytes. The IL-2-dependent growth was primarily observed in the IL-2R + thymic subset, which contains the CD3–/CD4–/CD8– precursor thymocytes. Furthermore, in vitro blocking of IL-2 in intact fetal thymic lobes resulted in a reduction in the cell yield, which predominantly affected the expansion of the immature CD3–/CD4–/CD8 – thymocytes. Our findings strongly support the concept that the IL-2/IL-2R pathway is responsible for the proliferation of precursor cells within the fetal thymus.

Original languageEnglish (US)
Pages (from-to)59-66
Number of pages8
JournalDevelopmental Immunology
Issue number1
StatePublished - 1990


  • IL-2
  • IL-2 receptor
  • T-cell development
  • precursor thymocytes

ASJC Scopus subject areas

  • Immunology
  • Developmental Biology


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