Pezzano M, Philp D, Stephenson S, Li Y, Reid V, Maitta R, Guyden J C
Department of Biology, City College of New York 10031, USA.
Cell Immunol. 1996 May 1;169(2):174-84. doi: 10.1006/cimm.1996.0108.
A temperature-sensitive line of thymic nurse cells (tsTNC-1) that maintains the ability to selectively internalize immature alpha beta TCRloCD4+CD8+ thymocytes in vitro was used in long-term coincubation experiments to determine nurse cell function during the process of MHC restriction. The thymocyte subset released from its association with TNCs contained both viable and apoptotic cells. The cells that remained within intracytoplasmic vacuoles died through the process of programmed cell death. Surviving or rescued thymocytes in the released population displayed an increase in Bcl-2 protein expression. The rescue activity of TNCs was drastically reduced with the addition of antibodies against either class I or class II MHC antigens to cocultures. A subset of the TNC-rescued population matured from the alpha beta TCRloCD69- phenotype to alpha beta TCRhiCD(69+)-expressing cells only when IL-1 beta was added to cocultures. These results suggest that TNC rescue of early double-positive thymocytes from apoptosis is associated with an interaction between the TCR and the MHC and the onset of Bcl-2 expression. Maturation of thymocytes within the TNC-rescued population requires the costimulatory effects of IL-1 beta.
利用一种温度敏感型胸腺哺育细胞系（tsTNC-1），该细胞系在体外保持选择性内化未成熟αβ TCRloCD4+CD8+胸腺细胞的能力，用于长期共孵育实验，以确定MHC限制过程中哺育细胞的功能。从与TNCs的结合中释放的胸腺细胞亚群包含存活细胞和凋亡细胞。留在胞质内空泡中的细胞通过程序性细胞死亡过程死亡。释放群体中存活或获救的胸腺细胞显示Bcl-2蛋白表达增加。在共培养物中加入针对I类或II类MHC抗原的抗体后，TNCs的拯救活性大幅降低。只有在共培养物中加入IL-1β时，TNC拯救群体的一个亚群才从αβ TCRloCD69-表型成熟为表达αβ TCRhiCD(69+)-的细胞。这些结果表明，TNC将早期双阳性胸腺细胞从凋亡中拯救出来与TCR和MHC之间的相互作用以及Bcl-2表达的开始有关。TNC拯救群体中胸腺细胞的成熟需要IL-1β的共刺激作用。
