Morphological analysis of the cellular interaction between thymocytes and a thymic stromal cell line (TEL-2)
✍ Scribed by Hirata, Kazuho ;Mori, Keiko ;Nakamura, Keiichiro ;Kawabuchi, Masaru ;Watanabe, Takeshi
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 909 KB
- Volume
- 230
- Category
- Article
- ISSN
- 0003-276X
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✦ Synopsis
Abstract
In a previous study (Nakashima et al., Eur. J. Immunol., 20: 47–53, 1990), a cloned stromal cell line TEL‐2 was established from Balb/c mouse thymus. Incubation of thymocytes with TEL‐2 cells resulted in the selective elimination of CD4 and CD8 double‐positive thymocytes from the culture. In the present report, both phase‐contrast and scanning electron microscopes were used to examine, at various time intervals, TEL‐2 cells cocultivated with thymocytes in order to elucidate the kinetic sequence of their cellular interaction. The thymocytes attached to the TEL‐2 cell surface were more numerous at early times (30 min to 1 h), and their number decreased gradually with time. In contrast, the thymocytes that migrated into the TEL‐2 cell layers were less abundant at early times, their number increasing with time thereafter. Destruction of the regular arrangement of TEL‐2 cells was found at later than 1 h, suggesting active cellular interaction. The thymocytes adherent to the TEL‐2 cell surface were found to be of various shapes and often showed variable profiles, e.g., extending small cytoplasmic processes along the surface of TEL‐2 cells or appearing ameboidal. A remarkable feature of the TEL‐2 cells was that they formed numerous “round spaces” at the surface of the TEL‐2 cell layers. The thymocytes were often located around “round spaces,” and some were seen migrating into TEL‐2 cell layers through these round spaces. In addition, complementary examinations by transmission electron microscopy revealed that the internalization of thymocytes into TEL‐2 cells occurs inside the TEL‐2 cell layers after migration. Thus, the present study confirmed the existence of a certain type of cellular interaction between thymocytes and TEL‐2 cells. The TEL‐2 cell line may provide a model system for the study of the selection mechanism in the process of T‐cell maturation.