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Interleukin‐7 treatment promotes the differentiation pathway of T‐cell‐receptor‐αβ cells selectively to the CD8 + cell lineage
Author(s) -
VARAS A.,
VICENTE A.,
JIMÉNEZ E.,
ALONSO L.,
MORENO J.,
MUÑOZ J. J.,
ZAPATA A. G.
Publication year - 1997
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.1997.00387.x
Subject(s) - lineage (genetic) , cd8 , cytotoxic t cell , microbiology and biotechnology , biology , cell , cellular differentiation , receptor , cell lineage , t cell , chemistry , immunology , genetics , immune system , gene , in vitro
In this report we have studied the influence of interleukin‐7 (IL‐7) on thymocyte differentiation by evaluating the effects of IL‐7 on the generation of T‐cell receptor‐αβ (TCR‐αβ) and TCR‐γδ thymocyte subpopulations in rat fetal thymus organ culture. IL‐7 enhanced the differentiation pathway of TCRαβ thymocytes, first increasing the numbers of immature CD8 + cells, and later those of both CD4 + CD8 + and mature thymocytes. The kinetics of thymocyte migration out of thymic lobes was also accelerated, and the average number of mature TCR‐αβ hi emigrants per day was increased in the presence of IL‐7. Moreover, mature CD4 − CD8 + thymocytes were preferentially generated after IL‐7 administration. This TCR‐αβ hi cell population was not actively dividing, indicating that IL‐7‐promoted thymocyte differentiation was selective to the CD8 cell lineage. Distribution of some TCR‐Vα and TCR‐Vβ segments among mature thymocytes was also modified in IL‐7‐treated thymic lobes. On the contrary, the maturation of TCR‐γδ was not affected by IL‐7 addition during the first days of culture, but their numbers sharply increased by day 6 of culture. These results were confirmed with IL‐7‐treated cultures for 24 hr, showing that IL‐7 responsiveness was acquired by TCR‐γδ cells late in thymus ontogeny. The present results thus indicate a key role for IL‐7 in the maturation of TCR‐αβ thymocytes and the expansion of thymic TCR‐γδ cells.