Open AccessNeoplastic thymic epithelial cells of human thymoma support T cell development from CD4 − CD8 − cells to CD4 + CD8 + cells in vitro
Author(s) -
Masayoshi Inoue,
Yoshitaka Fujii,
Meinoshin Okumura,
Yukiyasu Takeuchi,
Hiroyuki Shiono,
Shinichiro Miyoshi,
Hikaru Matsuda,
R Shirakura
Publication year - 1998
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1046/j.1365-2249.1998.00606.x
Subject(s) - thymoma , biology , cd8 , cytotoxic t cell , cd34 , immunology , in vitro , cancer research , antigen , stem cell , microbiology and biotechnology , biochemistry
Human thymoma is a thymic epithelial cell tumour which often contains a large number of immature T cells and is frequently associated with autoimmune diseases. Since thymic epithelial cells play key roles in the development and selection of T cells in the normal thymus, we hypothesized that the neoplastic thymic epithelial cells of thymoma may support T cell differentiation in the tumour. We characterized CD4 − CD8 − cells in thymoma and applied an in vitro reconstitution culture system using the CD4 − CD8 − cells and the neoplastic epithelial cells isolated from thymoma. CD34, a stem cell marker, was expressed on 29.9 ± 12.2% of CD4 − CD8 − cells in thymoma. TCRγδ was expressed on 27.4 ± 15.1% of CD4 − CD8 − cells and CD19, a B cell marker, was expressed on 14.1 ± 23.1% of CD4 − CD8 − cells. CD4 − CD8 − cells expressed both IL‐7R α‐chain and common γ‐chain. Purified CD4 − CD8 − cells from thymomas were cultured with the neoplastic epithelial cells, and their differentiation into CD4 + CD8 + cells via CD4 single‐positive intermediates was observed within 9 days' co‐culture in the presence of recombinant IL‐7. Furthermore, we examined the reconstitution culture using CD34 + CD4 − CD8 − cells purified from normal infant thymus. The CD34 + CD4 − CD8 − cells in normal thymus also differentiated to CD4 + CD8 + cells in the allogeneic co‐culture with the neoplastic epithelial cells of thymoma. These results indicate that the tumour cells of thymoma retain the function of thymic epithelial cells and can induce differentiation of T cells in thymoma.