Amarante-Mendes J G, Chammas R, Abrahamsohn P, Patel P C, Potworowski E F, Macedo M S
Institut Armand Frappier, Laval, Quebec, Canada.
Cell Immunol. 1995 Apr 1;161(2):173-80. doi: 10.1006/cimm.1995.1024.
A clone of thymic stromal cells, namely 2BH4, was established by primary culture, cellular transfection and limiting dilution. Morphological analysis by transmission electron microscopy revealed that these cells grow as multilayers, producing a well-defined basement membrane to which they attach and frequently form structures similar to hemidesmosomes. The adjoining cells are connected by intercellular junctions, as tight junctions, intermediate junctions, and desmosome-like junctions, as well as interdigitations. Their cytoplasm contains microtubules, strands of actin filaments, and scarce intermediate filaments. Fluorescence microscopy revealed that 2BH4 cells stain with anti-cytokeratin antibodies, the majority of them giving a faint reaction. In addition, they express Thy-1.1, LFA-1, ICAM-1, and the gp23 epithelial antigen, and synthesize laminin. They have a doubling time of 16 hr and are able to bind thymocytes. Thymocytes cultured in the presence of 2BH4 cells are partially protected from both spontaneous and PMA- or dexamethasone-induced apoptosis. This protection is conferred neither by soluble factors normally produced by the 2BH4 cells nor by the sole contact with fixed 2BH4 cells. Rather, thymocytes must interact with metabolically active 2BH4 cells in order to receive the protective signal(s).
通过原代培养、细胞转染和有限稀释法建立了一株胸腺基质细胞克隆，即2BH4。透射电子显微镜的形态学分析显示，这些细胞呈多层生长，产生一层明确的基底膜，它们附着于该基底膜并经常形成类似于半桥粒的结构。相邻细胞通过细胞间连接相连，如紧密连接、中间连接、类桥粒连接以及细胞交错连接。它们的细胞质含有微管、肌动蛋白丝束和少量中间丝。荧光显微镜检查显示，2BH4细胞用抗细胞角蛋白抗体染色，其中大多数呈弱阳性反应。此外，它们表达Thy-1.1、淋巴细胞功能相关抗原-1（LFA-1）、细胞间黏附分子-1（ICAM-1）和gp23上皮抗原，并合成层粘连蛋白。它们的倍增时间为16小时，并且能够结合胸腺细胞。在2BH4细胞存在的情况下培养的胸腺细胞对自发凋亡以及佛波酯（PMA）或地塞米松诱导的凋亡均有部分保护作用。这种保护作用既不是由2BH4细胞正常产生的可溶性因子赋予的，也不是仅通过与固定的2BH4细胞接触赋予的。相反，胸腺细胞必须与代谢活跃的2BH4细胞相互作用才能接收保护信号。
