Morphological analysis of the cellular interaction between thymocytes and a thymic stromal cell line (TEL-2).
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.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Anatomy, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
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Hirata
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Mori
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Nakamura
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Kawabuchi
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Watanabe
D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D003238:Connective Tissue / Q000502:physiology / Q000648:ultrastructure; D003239:Connective Tissue Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008858:Microscopy, Phase-Contrast; D013950:Thymus Gland / Q000166:cytology* / Q000502:physiology / Q000648:ultrastructure