Enhancement of IL-7 following irradiation of fetal thymus

Junko Toki, Yasushi Adachi, Tienan Jin, Tianxue Fan, Katsunori Takase, Zhexiong Lian, Haruki Hayashi, M. Eric Gershwin, Susumu Ikehara

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

The effect of ionizing radiation on intra-thymic T cell development was investigated using a fetal thymic organ culture (FTOC) method in vitro. When double-negative (DN) fetal (day 15) thymocytes were co-cultured with an irradiated (25 Gy) fetal (day 15) thymus in the absence of direct contact or mitogenic stimulation, the induction of TCRγδ+ T cells was observed. About 50% of the TCRγδ+ T cells developed after 4-day-co-culture with the irradiated fetal thymus, whereas only a few TCRγδ+ T cells developed after co-culture with the non-irradiated fetal thymus. About 50% of the TCRγδ+ T cells were CD8+ cells with αβ heterodimeric chains. Cultured supernatants of the irradiated fetal thymi also induced the differentiation from DN thymocytes to CD8+ TCRγδ+ T cells after 3-day-culture. To clarify the factor in the cultured supernatants, several neutralizing antibodies (Abs) were used. Only anti-IL-7-Ab inhibited the differentiation from DN thymocytes to CD8+ TCRγδ+ T cells. RTPCR revealed the increased expression of IL-7 mRNA in the fetal thymus 24 hours after radiation. Electron microscope studies demonstrated proliferative epithelial cells in the irradiated fetal thymus. These findings strongly suggest that fetal thymic epithelial cells affected by irradiation proliferate and enhance the production of IL-7, which induces the differentiation of CD8+ TCRγδ+ T cells from DN thymocytes.

Original languageEnglish (US)
Pages (from-to)247-258
Number of pages12
JournalImmunobiology
Volume207
Issue number4
DOIs
StatePublished - 2003

ASJC Scopus subject areas

  • Immunology

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  • Cite this

    Toki, J., Adachi, Y., Jin, T., Fan, T., Takase, K., Lian, Z., Hayashi, H., Gershwin, M. E., & Ikehara, S. (2003). Enhancement of IL-7 following irradiation of fetal thymus. Immunobiology, 207(4), 247-258. https://doi.org/10.1078/0171-2985-00242