van Eijk M, de Groot C
Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, The Netherlands.
J Immunol. 1999 Sep 1;163(5):2478-82.
Follicular dendritic cells (FDCs) select B cells during germinal center (GC) reactions. The B cells that are able to bind to the FDCs receive a signal that leads to the termination of endonuclease activity in the nuclei of those B cells. This signal must be in addition to the signals transferred through the cross-linkage of the B cell receptors and signals resulting from the interactions of the adhesion molecules lymphocyte function-associated Ag-1 and very late Ag-4 with ICAM-1 and VCAM-1, respectively. In this report, we present evidence that the FDCs silence all apoptotic processes in GC B lymphocytes and additionally switch off pre-present endonuclease activity. We also show that GC B cell apoptosis requires cathepsin activity downstream of caspase-3. This cathepsin activity is directly connected to endonuclease activity and therefore may be an interesting target for the antiapoptotic factors produced by FDCs.
滤泡树突状细胞（FDCs）在生发中心（GC）反应过程中选择B细胞。能够与FDCs结合的B细胞会接收到一个信号，该信号导致这些B细胞核内核酸酶活性终止。此信号必定是除了通过B细胞受体交联传递的信号以及分别由淋巴细胞功能相关抗原-1和极晚期抗原-4与细胞间黏附分子-1和血管细胞黏附分子-1相互作用产生的信号之外的信号。在本报告中，我们提供证据表明，FDCs使GC B淋巴细胞中的所有凋亡过程沉默，并额外关闭预先存在的核酸酶活性。我们还表明，GC B细胞凋亡需要半胱天冬酶-3下游的组织蛋白酶活性。这种组织蛋白酶活性与核酸酶活性直接相关，因此可能是FDCs产生的抗凋亡因子的一个有趣靶点。
